Glucose: Difference between revisions

{{cs1 config |name-list-style=vanc |display-authors=6}}

| ImageFile = Glucose D-glucose-chain structure-2D-skeletal.svgpng

| IUPACName = Allowed trivial names:<ref>[https://iupac.qmul.ac.uk/2carb/02.html Nomenclature of Carbohydrates (Recommendations 1996) {{!}} 2-Carb-2] {{Webarchive|url=https://web.archive.org/web/20230827082825/https://iupac.qmul.ac.uk/2carb/02.html |date=2023-08-27 August 2023 }}. ''iupac.qmul.ac.uk''.</ref>

| C=6 | H=12 | O=6

| Dipole = 810.68275674

| Entropy = 209.2&nbsp;J/(K·mol)<ref name="Boerio-Goates 1991 403–9">{{citation | last = Boerio-Goates | first = Juliana | title = Heat-capacity measurements and thermodynamic functions of crystalline α-D-glucose at temperatures from 10K to 340K | journal = J. Chem. Thermodyn. | year = 1991 | volume = 23 | issue = 5 | pages = 403–09 | doi = 10.1016/S0021-9614(05)80128-4| bibcode = 1991JChTh..23..403B }}</ref>

Glucose was first isolated from [[raisin]]s in 1747 by the German chemist [[Andreas Sigismund Marggraf|Andreas Marggraf]].<ref name="Encyclopedia of Food and Health">{{cite book|title=Encyclopedia of Food and Health|date=2015|publisher=Academic Press|isbn=978-0-12-384953-3|page=239|url=https://books.google.com/books?id=O-t9BAAAQBAJ&pg=RA2-PA239|language=en|url-status=live|archive-url=https://web.archive.org/web/20180223145046/https://books.google.com/books?id=O-t9BAAAQBAJ&pg=RA2-PA239|archive-date=2018-02-23 February 2018}}</ref><ref>Marggraf (1747) [https://books.google.com/books?id=lJQDAAAAMAAJ&pg=PA79 "Experiences chimiques faites dans le dessein de tirer un veritable sucre de diverses plantes, qui croissent dans nos contrées"] {{webarchive|url=https://web.archive.org/web/20160624083152/https://books.google.com/books?id=lJQDAAAAMAAJ&pg=PA79 |date=2016-06-24 June 2016 }} [Chemical experiments made with the intention of extracting real sugar from diverse plants that grow in our lands], ''Histoire de l'académie royale des sciences et belles-lettres de Berlin'', pp. 79–90. [https://archive.org/details/bub_gb_lJQDAAAAMAAJ/page/n114 From page 90:] {{webarchive|url=https://web.archive.org/web/20141027011957/http://books.google.com/books?id=lJQDAAAAMAAJ&pg=PA90 |date=2014-10-27 October 2014 }} ''"Les raisins secs, etant humectés d'une petite quantité d'eau, de maniere qu'ils mollissent, peuvent alors etre pilés, & le suc qu'on en exprime, etant depuré & épaissi, fournira une espece de Sucre."'' ("Raisins, being moistened with a small quantity of water, in a way that they soften, can be then pressed, and the juice that is squeezed out, [after] being purified and thickened, will provide a sort of sugar.")</ref> Glucose was discovered in grapes by another German chemist{{Snd}}[[Johann Tobias Lowitz]]{{Snd}}in 1792, and distinguished as being different from cane sugar ([[sucrose]]). Glucose is the term coined by [[Jean Baptiste Dumas]] in 1838, which has prevailed in the chemical literature. [[Friedrich August Kekulé]] proposed the term dextrose (from the [[Latin]] {{lang|la|dexter}}, meaning "right"), because in aqueous solution of glucose, the plane of linearly polarized light is turned to the right. In contrast, [[l-fructose]] (usually referred to as {{sm|d}}-fructose) (a ketohexose) and l-glucose ({{sm|l}}-glucose) turn linearly [[Polarization (physics)|polarized]] light to the left. The earlier notation according to the rotation of the plane of linearly polarized light (''d'' and ''l''-nomenclature) was later abandoned in favor of the [[optical rotation#Chirality prefixes|{{sm|d}}- and {{sm|l}}-notation]], which refers to the absolute configuration of the asymmetric center farthest from the carbonyl group, and in concordance with the configuration of {{sm|d}}- or {{sm|l}}-glyceraldehyde.<ref name="Robyt 7">John F. Robyt: ''Essentials of Carbohydrate Chemistry.''. Springer Science & Business Media, 2012, {{ISBN|978-1-461-21622-3}}. p. 7.</ref><ref name="Rosanoff">{{Cite journal|doi=10.1021/ja01967a014|title=On Fischer's Classification of Stereo-Isomers.1|journal=Journal of the American Chemical Society|volume=28|pages=114–121|year=1906|last1=Rosanoff|first1=M. A.|url=https://zenodo.org/record/1428874|access-date=1 July 2019-07-01|archive-date=2019-12-17 December 2019|archive-url=https://web.archive.org/web/20191217170142/https://zenodo.org/record/1428874|url-status=live}}</ref>

Since glucose is a basic necessity of many organisms, a correct understanding of its [[chemical]] makeup and structure contributed greatly to a general advancement in [[organic chemistry]]. This understanding occurred largely as a result of the investigations of [[Hermann Emil Fischer|Emil Fischer]], a German chemist who received the 1902 [[Nobel Prize in Chemistry]] for his findings.<ref>{{citation | title = Emil Fischer | url = http://nobelprize.org/nobel_prizes/chemistry/laureates/1902/fischer-bio.html | publisher = Nobel Foundation | access-date = 2 September 2009-09-02 | url-status = live | archive-url = https://web.archive.org/web/20090903164859/http://nobelprize.org/nobel_prizes/chemistry/laureates/1902/fischer-bio.html | archive-date = 3 September 2009-09-03 }}</ref> The synthesis of glucose established the structure of organic material and consequently formed the first definitive validation of [[Jacobus Henricus van 't Hoff]]'s theories of chemical kinetics and the arrangements of chemical bonds in carbon-bearing molecules.<ref>{{citation | title = van't Hoff's Glucose | first = Bert | last = Fraser-Reid | journal = Chem. Eng. News | volume = 77 | issue = 39 | page = 8}}</ref> Between 1891 and 1894, Fischer established the [[stereochemical]] configuration of all the known sugars and correctly predicted the possible [[isomer]]s, applying [[Van 't Hoff's theoryequation]] of asymmetrical carbon atoms. The names initially referred to the natural substances. Their [[enantiomers]] were given the same name with the introduction of systematic nomenclatures, taking into account absolute stereochemistry (e.g. [[Fischer projection|Fischer nomenclature]], {{sm|d}}/{{sm|l}} nomenclature).

For the discovery of the metabolism of glucose [[Otto Meyerhof]] received the [[Nobel Prize in Physiology or Medicine]] in 1922.<ref>[https://www.nobelprize.org/nobel_prizes/medicine/laureates/1922/meyerhof-facts.html "Otto Meyerhof - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180715011915/https://www.nobelprize.org/nobel_prizes/medicine/laureates/1922/meyerhof-facts.html |date=2018-07-15 July 2018 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref> [[Hans von Euler-Chelpin]] was awarded the Nobel Prize in Chemistry along with [[Arthur Harden]] in 1929 for their "research on the [[fermentation]] of sugar and their share of enzymes in this process".<ref>[https://www.nobelprize.org/prizes/chemistry/1929/euler-chelpin/facts/ "Hans von Euler-Chelpin - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180903153041/https://www.nobelprize.org/prizes/chemistry/1929/euler-chelpin/facts/ |date=3 September 2018-09-03 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref><ref>[https://www.nobelprize.org/prizes/chemistry/1929/harden/facts/ "Arthur Harden - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180903151549/https://www.nobelprize.org/prizes/chemistry/1929/harden/facts/ |date=3 September 2018-09-03 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref> In 1947, [[Bernardo Houssay]] (for his discovery of the role of the [[pituitary gland]] in the metabolism of glucose and the derived carbohydrates) as well as [[Carl Cori|Carl]] and [[Gerty Cori]] (for their discovery of the conversion of glycogen from glucose) received the Nobel Prize in Physiology or Medicine.<ref>[https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/houssay-facts.html "Bernardo Houssay - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180715011905/https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/houssay-facts.html |date=2018-07-15 July 2018 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref><ref>[https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/cori-cf-facts.html "Carl Cori - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180715035943/https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/cori-cf-facts.html |date=2018-07-15 July 2018 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref><ref>[https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/cori-gt-facts.html "Gerty Cori - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180715011845/https://www.nobelprize.org/nobel_prizes/medicine/laureates/1947/cori-gt-facts.html |date=2018-07-15 July 2018 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref> In 1970, [[Luis Leloir]] was awarded the Nobel Prize in Chemistry for the discovery of glucose-derived sugar nucleotides in the biosynthesis of carbohydrates.<ref>[https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1970/leloir-facts.html "Luis Leloir - Facts - NobelPrize.org"] {{Webarchive|url=https://web.archive.org/web/20180715035858/https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1970/leloir-facts.html |date=2018-07-15 July 2018 }}. ''NobelPrize.org''. Retrieved on 5 September 2018.</ref>

Glucose forms white or colorless solids that are highly [[Solubility|soluble]] in water and [[acetic acid]] but poorly soluble in [[methanol]] and [[ethanol]]. They melt at {{convert|146|C|F}} (''α'') and {{convert|150|C|F}} (''beta''), [[Chemical decomposition|decompose]] starting at {{convert|188|C|F}} with release of various volatile products, ultimately leaving a residue of [[carbon]].<ref name=kang2020>Wenyue Kang and Zhijun Zhang (2020): "Selective Production of Acetic Acid via Catalytic Fast Pyrolysis of Hexoses over Potassium Salts", ''Catalysts'', volume 10, pages 502–515. {{doi|10.3390/catal10050502}}</ref> Glucose has a [[acid strength|pKa value]] of 12.16 at {{cvt|25|C}} in water.<ref>{{Citecite journal |last1=Bosch |first1=L.I. |last2=Fyles |first2=T.M. |last3=James |first3=T.D.|date=2004 |title=Binary and ternary phenylboronic acid complexes with saccharides and Lewis bases|url=http://dx.doi.org/10.1016/j.tet.2004.08.046 |journal=Tetrahedron |date=November 2004 |volume=60 |issue=49 |pages=11175–11190 |doi=10.1016/j.tet.2004.08.046|issn=0040-4020|url-access=subscription }}</ref>

With six carbon atoms, it is classed as a [[hexose]], a subcategory of the [[monosaccharide]]s. {{sm|d}}-Glucose is one of the sixteen [[aldohexose]] [[stereoisomer]]s. The {{sm|d}}-[[isomer]], {{sm|d}}-glucose, also known as dextrose, occurs widely in nature, but the {{sm|l}}-isomer, [[L-glucose|{{sm|l}}-glucose]], does not. Glucose can be obtained by [[hydrolysis]] of carbohydrates such as milk sugar ([[lactose]]), cane sugar (sucrose), [[maltose]], [[cellulose]], [[glycogen]], etc. Dextrose is commonly commercially manufactured from [[Starch|starches]], such as [[corn starch]] in the US and Japan, from potato and wheat starch in Europe, and from [[tapioca starch]] in tropical areas.<ref>{{Citation|last=Yebra-Biurrun|first=M.C.|title=Sweeteners|date=2005|encyclopedia=Encyclopedia of Analytical Science|pages=562–572|publisher=Elsevier|language=en|doi=10.1016/b0-12-369397-7/00610-5|isbn=978-0-12-369397-6}}</ref> The manufacturing process uses hydrolysis via pressurized steaming at controlled [[pH]] in a jet followed by further enzymatic depolymerization.<ref>"glucose." The Columbia Encyclopedia, 6th ed.. 2015. Encyclopedia.com. 17 Nov.November 2015 http://www.encyclopedia.com {{webarchive|url=https://web.archive.org/web/20090426025317/http://www.encyclopedia.com/ |date=2009-04-26 April 2009 }}.</ref> Unbonded glucose is one of the main ingredients of [[honey]].<ref>{{cite journal | doi=10.1002/efd2.71 | title=Comprehensive review on functional and nutraceutical properties of honey | date=2023 | journal=Efood | volume=4 | issue=2 | vauthors = Aga MB, Sharma V, Dar AH, Dash KK, Singh A, Shams R, Khan SA | doi-access=free }}</ref><ref>{{cite journal | doi=10.1155/2018/4757893 | title=Honey and Diabetes: The Importance of Natural Simple Sugars in Diet for Preventing and Treating Different Type of Diabetes | date=2018 | journal=Oxidative Medicine and Cellular Longevity | volume=2018 | pages=1–12 | pmid=29507651 | pmc=5817209 | vauthors = Bobiş O, Dezmirean DS, Moise AR | doi-access=free }}</ref><ref>{{cite book | chapter-url=https://link.springer.com/chapter/10.1007/978-981-15-7305-7_9 | doi=10.1007/978-981-15-7305-7_9 | chapter=Scope of Honey in Diabetes and Metabolic Disorders | title=Therapeutic Applications of Honey and its Phytochemicals | date=2020 | pages=195–217 | isbn=978-981-15-7304-0 | vauthors = Wani HA, Majid S, Khan MS, Bhat AA, Wani RA, Bhat SA, Ali S, Rehman MU | publisher=Springer | access-date=2024-03-18 | archive-date=2021-04-14 | archive-url=https://web.archive.org/web/20210414044738/https://link.springer.com/chapter/10.1007/978-981-15-7305-7_9 | url-status=live }}</ref><ref>{{cite journal | url=https://link.springer.com/article/10.1007/s12349-009-0051-6 | doi=10.1007/s12349-009-0051-6 | title=Contribution of honey in nutrition and human health: A review | date=2010 | journal=Mediterranean Journal of Nutrition and Metabolism | volume=3 | pages=15–23 | vauthors = Alvarez-Suarez JM, Tulipani S, Romandini S, Bertoli E, Battino M | access-date=2024-03-18 | archive-date=2024-02-12 | archive-url=https://web.archive.org/web/20240212171745/https://link.springer.com/article/10.1007/s12349-009-0051-6 | url-status=live }}</ref><ref>{{Citecite journal |doilast1=10.1016/j.jada.2006.05.003Ischayek |urlfirst1=https://www.jandonline.org/article/S0002-8223(06)00879-0/abstractJennifer Ilana |last2=Kern |first2=Mark |title=US Honeys Varying in Glucose and Fructose Content Elicit Similar Glycemic Indexes - |journal=Journal of the American Dietetic Association |date=August 2006 |pmid=16863724 |journal=Journal of the American Dietetic Association |volume=106 |issue=8 |pages=1260–1262 |doi=10.1016/j.jada.2006.05.003 vauthors |pmid= Ischayek JI, Kern M16863724 }}</ref>

The term ''dextrose'' is often used in a clinical (related to patient's health status) or nutritional context (related to dietary intake, such as food labels or dietary guidelines), while "glucose" is used in a biological or physiological context (chemical processes and molecular interactions),<ref>{{Cite web |url=https://diabetesjournals.org/care/article/28/4/981/23717/Potentially-Important-Contribution-of-Dextrose |title=Potentially Important Contribution of Dextrose Used as Diluent to Hyperglycemia in Hospitalized Patients &#124; Diabetes Care &#124; American Diabetes Association |access-date=2024-03-18 March 2024 |archive-date=2022-05-29 May 2022 |archive-url=https://web.archive.org/web/20220529014858/https://diabetesjournals.org/care/article/28/4/981/23717/Potentially-Important-Contribution-of-Dextrose |url-status=live }}</ref><ref>{{cite web | url=https://www.medicalnewstoday.com/articles/322243 | title=Dextrose: Why is it in food and medicine? | date=24 June 2018 | access-date=18 March 2024 | archive-date=13 February 2024 | archive-url=https://web.archive.org/web/20240213110503/https://www.medicalnewstoday.com/articles/322243 | url-status=live }}</ref><ref name="wid">{{cite web | url=https://thenutritioninsider.com/wellness/what-is-dextrose/ | title=What is Dextrose, How is It Used, and is It Healthy? - the Nutrition Insider | date=27 October 2023 | access-date=18 March 2024 | archive-date=14 February 2024 | archive-url=https://web.archive.org/web/20240214235338/https://thenutritioninsider.com/wellness/what-is-dextrose/ | url-status=live }}</ref><ref>{{cite web | url=https://www.livestrong.com/article/534228-glucose-vs-dextrose/ | title=Dextrose vs. Glucose: Are These Sugars Equal? | access-date=2024-03-18 March 2024 | archive-date=2023-09-29 September 2023 | archive-url=https://web.archive.org/web/20230929231815/https://www.livestrong.com/article/534228-glucose-vs-dextrose/ | url-status=live }}</ref> but both terms refer to the same molecule, specifically D-glucose.<ref name="wid"/><ref name="pmid938892">{{cite journal | pmid=938892 | date=1976 | last1=Baron | first1=D. N. | last2=McIntyre | first2=N. | title=Letter: Glucose is dextrose is glucose | journal=British Medical Journal | volume=2 | issue=6026 | pages=41–42 | doi=10.1136/bmj.2.6026.41-c | pmc=1687736 }}</ref>

''Dextrose monohydrate'' is the hydrated form of D-glucose, meaning that it is a glucose molecule with an additional water molecule attached.<ref name="chem"/> Its chemical formula is {{chem2|C6H12O6}}&nbsp;·&nbsp;{{chem2|H2O}}.<ref name="chem"/><ref name="api110617">{{cite web | url=https://www.cdek.liu.edu/api/110617/ | title=API &#124; glucose monohydrate | access-date=2024-03-18 March 2024 | archive-date=2023-03-24 March 2023 | archive-url=https://web.archive.org/web/20230324200604/https://www.cdek.liu.edu/api/110617/ | url-status=live }}</ref> Dextrose monohydrate is also called ''hydrated D-glucose'', and commonly manufactured from plant starches.<ref name="chem">{{cite web | url=https://www.pciplindia.com/product-detail/Dextrose-Monohydrate- | title=Prakash Chemicals International | access-date=2024-03-18 March 2024 | archive-date=6 June 2023-06-06 | archive-url=https://web.archive.org/web/20230606204745/https://www.pciplindia.com/product-detail/Dextrose-Monohydrate- | url-status=live }}</ref><ref name="diff">{{cite web | url=https://gtspfood.com/en/the-difference-between-dextrose-anhydrous-and-dextrose-monohydrate/ | title=The difference between dextrose anhydrous and dextrose monohydrate | date=28 December 2022 | access-date=18 March 2024 | archive-date=18 March 2024 | archive-url=https://web.archive.org/web/20240318213001/https://gtspfood.com/en/the-difference-between-dextrose-anhydrous-and-dextrose-monohydrate/ | url-status=live }}</ref> Dextrose monohydrate is utilized as the predominant type of dextrose in food applications, such as beverage mixes—it is a common form of glucose widely used as a nutrition supplement in production of foodstuffs. Dextrose monohydrate is primarily consumed in North America as a [[corn syrup]] or [[high-fructose corn syrup]].<ref name="wid" />

''Anhydrous dextrose'', on the other hand, is glucose that does not have any water molecules attached to it.<ref name="diff"/> <ref name="ahn1">{{Cite web|url=https://www.chembk.com/en/chem/Dextrose%20anhydrous|title=Dextrose anhydrous|access-date=2024-03-18 March 2024|archive-date=2024-03-18 March 2024|archive-url=https://web.archive.org/web/20240318212942/https://www.chembk.com/en/chem/Dextrose%20anhydrous|url-status=live}}</ref> Anhydrous chemical substances are commonly produced by eliminating water from a hydrated substance through methods such as heating or drying up (desiccation).<ref>{{cite journal |last1=Khvorova url|first1=https://linkL.springer S.com/article/10 |last2=Andreev |first2=N. R.3103/S1068367420010048 |last3=Lukin doi|first3=10N.3103/S1068367420010048 |D. |title=Study of Conditions for Applying Surfactants in Crystalline Glucose Production | date=2020 | journal=Russian Agricultural Sciences |date=January 2020 |volume=46 | issue=1 | pages=90–93 |doi=10.3103/S1068367420010048 |bibcode=2020RuAgS..46...90K | vauthors=Khvorova LS, Andreev NR, Lukin ND | access-date=2024-03-18 | archive-date=2024-03-18 | archive-url=https://web.archive.org/web/20240318212935/https://link.springer.com/article/10.3103/S1068367420010048 | url-status=live }}</ref><ref name="a2">{{cite web | url=https://topic.echemi.com/a/what-is-the-difference-between-anhydrous-glucose-and-glucose_176447.html | title=What is the difference between anhydrous glucose and glucose | access-date=2024-03-18 March 2024 | archive-date=2024-03-18 March 2024 | archive-url=https://web.archive.org/web/20240318212829/https://topic.echemi.com/a/what-is-the-difference-between-anhydrous-glucose-and-glucose_176447.html | url-status=live }}</ref><ref>{{cite web | url=https://thisvsthat.io/anhydrous-vs-monohydrate | title=Anhydrous vs. Monohydrate - What's the Difference? | access-date=2024-03-18 March 2024 | archive-date=2024-03-18 March 2024 | archive-url=https://web.archive.org/web/20240318215004/https://thisvsthat.io/anhydrous-vs-monohydrate | url-status=live }}</ref> Dextrose monohydrate can be dehydrated to anhydrous dextrose in industrial setting.<ref>{{Citecite journal |doilast1=10Trasi |first1=Niraj S.1016/j |last2=Boerrigter |first2=Stephan X.ijpharmM.2010.12 |last3=Byrn |first3=Stephen R.042 |urllast4=https://wwwCarvajal |first4=Teresa M.sciencedirect.com/science/article/pii/S0378517311000160 |title=Investigating the effect of dehydration conditions on the compactability of glucose - ScienceDirect |journal=International Journal of Pharmaceutics |date=15 March 2011 |volume=406 |issue=11–2 |pages=55–61 |pmiddoi=21232587 |vauthors=Trasi NS, Boerrigter SX, Byrn SR, Carvajal TM |access-date=18 March 2024 |archive-date=18 March 2024 |archive-url=https:10.1016//webj.archiveijpharm.org/web/20240318213509/https://www2010.sciencedirect12.com/science/article/abs/pii/S0378517311000160042 |url-statuspmid=live21232587 }}</ref><ref>{{cite journal |last1=Mitra url|first1=https://www.tandfonline.com/doi/abs/10.1080/03639045.2017.1414231Biplob |last2=Wolfe doi|first2=10.1080/03639045.2017.1414231Chad |last3=Wu |first3=Sy-Juen |title=Dextrose monohydrate as a non-animal sourced alternative diluent in high shear wet granulation tablet formulations | date=2018 | journal=Drug Development and Industrial Pharmacy |date=4 May 2018 |volume=44 | issue=5 | pages=817–828 | pmiddoi=29300107 | vauthors=Mitra B, Wolfe C, Wu S | access-date=2024-03-18 | archive-date=2024-03-18 | archive-url=https://web.archive.org/web/20240318213503/https://www.tandfonline.com/doi/abs/10.1080/03639045.2017.1414231 | url-statuspmid=live29300107 }}</ref> Dextrose monohydrate is composed of approximately 9.5% water by mass; through the process of dehydration, this water content is eliminated to yield anhydrous (dry) dextrose.<ref name="diff"/>

Anhydrous dextrose has the chemical formula {{chem2|C6H12O6}}, without any water molecule attached which is the same as glucose.<ref name="chem"/> Anhydrous dextrose on open air tends to absorb moisture and transform to the monohydrate, and it is more expensive to produce.<ref name="diff"/> Anhydrous dextrose (anhydrous D-glucose) has increased stability and increased shelf life,<ref name="a2"/> has medical applications, such as in oral [[glucose tolerance test]] (OGTT).<ref>{{cite web | url=https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/diabetes/diabetes-prediabetes | title=Diabetes & Prediabetes Tests - NIDDK | access-date=2024-03-18 March 2024 | archive-date=2023-12-16 December 2023 | archive-url=https://web.archive.org/web/20231216120841/https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/diabetes/diabetes-prediabetes | url-status=live }}</ref>

Whereas molecular weight (molar mass) for D-glucose monohydrate is 198.17 g/mol,<ref>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/22814120 | title=Dextrose Monohydrate | access-date=2024-03-18 March 2024 | archive-date=2 December 2023-12-02 | archive-url=https://web.archive.org/web/20231202032815/https://pubchem.ncbi.nlm.nih.gov/compound/22814120 | url-status=live }}</ref><ref>{{Cite web |url=https://www.sigmaaldrich.com/MD/en/product/mm/108342 |title=D-(+)-glucose monohydrate |access-date=2024-03-18 March 2024 |archive-date=2024-03-18 March 2024 |archive-url=https://web.archive.org/web/20240318213348/https://www.sigmaaldrich.com/US/en/product/mm/108342 |url-status=live }}</ref> that for anhydrous D-glucose is 180.16 g/mol<ref>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/5793 | title=D-Glucose | access-date=2024-03-18 March 2024 | archive-date=2023-12-15 December 2023 | archive-url=https://web.archive.org/web/20231215173911/https://pubchem.ncbi.nlm.nih.gov/compound/5793 | url-status=live }}</ref><ref>{{Cite web |url=https://www.sigmaaldrich.com/MD/en/product/mm/137048 |title=D-(+)-Glucose |access-date=2024-03-18 March 2024 |archive-date=2024-03-18 March 2024 |archive-url=https://web.archive.org/web/20240318213459/https://www.sigmaaldrich.com/US/en/product/mm/137048 |url-status=live }}</ref><ref>{{Cite web |url=https://www.sigmaaldrich.com/MD/en/product/mm/108337 |title=D-(+)-Glucose |access-date=2024-03-18 March 2024 |archive-date=2024-03-18 March 2024 |archive-url=https://web.archive.org/web/20240318213357/https://www.sigmaaldrich.com/US/en/product/mm/108337 |url-status=live }}</ref> The density of these two forms of glucose is also different.{{specify|date=March 2024}}

In terms of chemical structure, glucose is a [[monosaccharide]], that is, a simple sugar. Glucose contains six carbon atoms and an [[aldehyde group]], and is therefore an [[aldohexose]]. The glucose molecule can exist in an [[Open-chain compound|open-chain]] (acyclic) as well as ring (cyclic) form—due to the presence of [[Alcohol (chemistry)|alcohol]] and [[aldehyde]] or [[ketone]] functional groups, the form having the straight chain can easily convert into a chair-like [[hemiacetal]] ring structure commonly found in carbohydrates.<ref name="chem2">{{cite web | url=https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_%28Biological_Chemistry%29/Carbohydrates/Monosaccharides/Glucose_%28Dextrose%29 | title=Glucose (Dextrose) | date=2 October 2013 | access-date=18 March 2024 | archive-date=21 December 2023 | archive-url=https://web.archive.org/web/20231221223258/https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Carbohydrates/Monosaccharides/Glucose_(Dextrose) | url-status=live }}</ref>

| align="center" rowspan="2" | [[File:D-Glucose Keilstrich.svg|100px|class=skin-invert-image]]

| align="center" | [[File:Alpha-D-Glucofuranose.svg|120px|class=skin-invert-image]]{{pb}}α-{{sm|d}}-glucofuranose

| align="center" | [[File:Beta-D-Glucofuranose.svg|120px|class=skin-invert-image]]{{pb}}β-{{sm|d}}-glucofuranose

| align="center" | [[File:Alpha-D-Glucopyranose.svg|100px|class=skin-invert-image]]{{pb}}α-{{sm|d}}-glucopyranose

| align="center" | [[File:Beta-D-Glucopyranose.svg|100px|class=skin-invert-image]]{{pb}}β-{{sm|d}}-glucopyranose

| align="center" colspan="3" | [[File:Alpha glucose views.svg|500px|class=skin-invert-image]]

[[Image:Glucose Fisher to Haworth.gif|thumb|class=skin-invert-image|Glucose can exist in both a straight-chain and ring form.]]

A open-chain form of glucose makes up less than 0.02% of the glucose molecules in an aqueous solution at equilibrium.<ref>{{Cite web |date=2014-07-18 July 2014 |title=16.4: Cyclic Structures of Monosaccharides |url=https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Basics_of_General_Organic_and_Biological_Chemistry_(Ball_et_al.)/16%3A_Carbohydrates/16.04%3A_Cyclic_Structures_of_Monosaccharides |access-date=17 April 2023-04-17 |website=Chemistry LibreTexts |language=en |archive-date=17 April 2023-04-17 |archive-url=https://web.archive.org/web/20230417213903/https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Basics_of_General_Organic_and_Biological_Chemistry_(Ball_et_al.)/16:_Carbohydrates/16.04:_Cyclic_Structures_of_Monosaccharides |url-status=live }}</ref> The rest is one of two cyclic hemiacetal forms. In its [[open-chain]] form, the glucose molecule has an open (as opposed to [[cyclic compound|cyclic]]) unbranched backbone of six carbon atoms, where C-1 is part of an [[aldehyde group]] {{chem2|H(C\dO)\s}}. Therefore, glucose is also classified as an [[aldose]], or an [[aldohexose]]. The aldehyde group makes glucose a [[reducing sugar]] giving a positive reaction with the [[Fehling test]].

[[File:Alpha-D-glucose and beta-D-glucose acid-catalyzed mechanism.svg|centre|500px|class=skin-invert-image|Widely proposed arrow-pushing mechanism for acid-catalyzed dynamic equilibrium between the α- and β- [[anomer]]s of D-glucopyranose]]

}}</div>

[[File:Mutarotation D-Glucose V.1.png|thumb|upright=2|class=skin-invert-image|Mutarotation: {{sm|d}}-glucose molecules exist as cyclic hemiacetals that are epimeric (= diastereomeric) to each other. The epimeric ratio α:β is 36:64. In the α-D-glucopyranose (left), the blue-labelled hydroxy group is in the axial position at the anomeric centre, whereas in the β-D-glucopyranose (right) the blue-labelled hydroxy group is in equatorial position at the anomeric centre.]]

Note that theThe {{sm|d}}- prefix does not refer directly to the optical properties of the compound. It indicates that the C-5 chiral centre has the same handedness as that of [[glyceraldehyde|{{sm|d}}-glyceraldehyde]] (which was so labelled because it is dextrorotatory). The fact that {{sm|d}}-glucose is dextrorotatory is a combined effect of its four chiral centres, not just of C-5; and indeed some of the other {{sm|d}}-aldohexoses are levorotatory.<!--CHECK-->

[[File:Glucose Fructose Mannose Gleichgewicht.png|frameless|upright=2.0|class=skin-invert-image|Glucose-Fructose-Mannose-isomerisation]]

|[[File:Metabolism of common monosaccharides, and related reactions.png|none|1000px|class=skin-invert-image]]

Glucose is the most abundant monosaccharide. Glucose is also the most widely used aldohexose in most living organisms. One possible explanation for this is that glucose has a lower tendency than other aldohexoses to react nonspecifically with the [[amine]] groups of [[protein]]s.<ref name=Higgins>{{cite journal|last1=Bunn|first1=H. F.|last2=Higgins|first2=P. J.|title=Reaction of monosaccharides with proteins: possible evolutionary significance |journal=Science|date=1981|volume=213 |issue=4504|pages=222–24|doi=10.1126/science.12192669|pmid=12192669| bibcode=1981Sci...213..222B}}<!--|access-date=13 May 2015--></ref> This reaction—[[glycation]]—impairs or destroys the function of many proteins,<ref name=Higgins/> e.g. in [[glycated hemoglobin]]. Glucose's low rate of glycation can be attributed to its having a more stable [[#Cyclic forms|cyclic form]] compared to other aldohexoses, which means it spends less time than they do in its reactive [[#Open-chain form|open-chain form]].<ref name=Higgins/> The reason for glucose having the most stable cyclic form of all the aldohexoses is that its [[hydroxy group]]s (with the exception of the hydroxy group on the anomeric carbon of {{sm|d}}-glucose) are in the [[Cyclohexane conformation|equatorial position]]. Presumably, glucose is the most abundant natural monosaccharide because it is less glycated with proteins than other monosaccharides.<ref name=Higgins /><ref name="Stryer 531">Jeremy M. Berg: ''Stryer Biochemie.'' {{In lang|de}}. Springer-Verlag, 2017, {{ISBN|978-3-662-54620-8}}, p.&nbsp;531. (German)</ref> Another hypothesis is that glucose, being the only {{sm|d}}-aldohexose that has all five hydroxy substituents in the [[Equatorial bond|equatorial]] position in the form of β-{{sm|d}}-glucose, is more readily accessible to chemical reactions,<ref name="Garrett">{{cite book |last1=Garrett |first1=Reginald H. |title=Biochemistry |date=2013 |publisher=Brooks/Cole, Cengage Learning |location=Belmont, CA |isbn=978-1-133-10629-6 |edition=5th}}</ref>{{rp|194, 199}} for example, for [[esterification]]<ref name=Voet>{{cite book |last1=Voet |first1=Donald |last2=Voet |first2=Judith G. |title=Biochemistry |date=2011 |publisher=John Wiley & Sons |location=Hoboken, NJ |isbn=978-0-470-57095-1 |edition=4th}}</ref>{{rp|363}} or [[acetal]] formation.<ref>Albert L. Lehninger, ''Biochemistry, 6th printing'', Worth Publishers Inc. 1972, {{ISBN|0-87901-009-6}} p. 228.</ref> For this reason, {{sm|d}}-glucose is also a highly preferred building block in natural polysaccharides (glycans). Polysaccharides that are composed solely of glucose are termed [[glucan]]s.

Glucose is produced by plants through photosynthesis using sunlight,<ref name="photo"/><ref name="Löffler/Petrides 195"/> water and carbon dioxide and can be used by all living organisms as an energy and carbon source. However, most glucose does not occur in its free form, but in the form of its polymers, i.e. lactose, sucrose, starch and others which are energy reserve substances, and cellulose and [[chitin]], which are components of the cell wall in plants or [[fungi]] and [[arthropod]]s, respectively. These polymers, when consumed by animals, fungi and bacteria, are degraded to glucose using enzymes. All animals are also able to produce glucose themselves from certain precursors as the need arises. [[Neuron]]s, cells of the [[renal medulla]] and [[erythrocytes]] depend on glucose for their energy production.<ref name="Löffler/Petrides 195">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.'' {{In lang|de}}.. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;195. (German)</ref> In adult humans, there is about {{cvt|18|g}} of glucose,<ref name="Satyanarayana">U. Satyanarayana: ''Biochemistry.''. Elsevier Health Sciences, 2014, {{ISBN|978-8-131-23713-7}}. p. 674.</ref> of which about {{cvt|4|g}} is present in the blood.<ref>{{Cite journal |doi=10.1152/ajpendo.90563.2008 |pmc=2636990 |pmid=18840763|year=2009 |last1=Wasserman |first1=D. H. |title=Four grams of glucose |journal=American Journal of Physiology. Endocrinology and Metabolism |volume=296 |issue=1 |pages=E11–21 }}</ref> Approximately {{cvt|180-220|g}} of glucose is produced in the liver of an adult in 24 hours.<ref name="Satyanarayana" />

Many of the long-term complications of [[diabetes]] (e.g., [[Visual impairment|blindness]], [[kidney failure]], and [[peripheral neuropathy]]) are probably due to the glycation of proteins or [[lipid]]s.<ref>{{citation | title = High Blood Glucose and Diabetes Complications: The buildup of molecules known as AGEs may be the key link | journal = Diabetes Forecast | url = http://forecast.diabetes.org/magazine/features/high-blood-glucose-and-diabetes-complications | year = 2010 | publisher = American Diabetes Association | issn = 0095-8301 | access-date = 2010-05-20 May 2010 | archive-url = https://web.archive.org/web/20131014173838/http://forecast.diabetes.org/magazine/features/high-blood-glucose-and-diabetes-complications | archive-date = 2013-10-14 October 2013 | url-status = dead }}</ref> In contrast, [[enzyme]]-regulated addition of sugars to protein is called [[glycosylation]] and is essential for the function of many proteins.<ref name="varki">{{Cite book|edition = 2nd|publisher = Cold Spring Harbor Laboratories Press|isbn = 978-0-87969-770-9| editor-first= Ajit |editor-last=Varki |title = Essentials of Glycobiology|url = https://www.ncbi.nlm.nih.gov/books/NBK1908/|url-status = live|archive-url = https://web.archive.org/web/20161206081633/https://www.ncbi.nlm.nih.gov/books/NBK1908/|archive-date = 6 December 2016-12-06|year = 2009| pmid=20301239 | last1=Varki | first1=A. | last2=Cummings | first2=R. D. | last3=Esko | first3=J. D. | last4=Freeze | first4=H. H. | last5=Stanley | first5=P. | last6=Bertozzi | first6=C. R. | last7=Hart | first7=G. W. | last8=Etzler | first8=M. E. }}</ref>

Ingested glucose initially binds to the receptor for sweet taste on the tongue in humans. This complex of the proteins [[T1R2]] and [[T1R3]] makes it possible to identify glucose-containing food sources.<ref name="fca">{{cite web | url=https://foodb.ca/compounds/FDB012530 | title=Showing Compound D-Glucose (FDB012530) - FooDB | access-date=2024-03-18 March 2024 | archive-date=6 December 2022-12-06 | archive-url=https://web.archive.org/web/20221206084746/https://www.foodb.ca/compounds/FDB012530 | url-status=live }}</ref><ref name="Löffler/Petrides 404"/> Glucose mainly comes from food—about {{cvt|300|g}} per day is produced by conversion of food,<ref name="Löffler/Petrides 404">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.''. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;404.</ref> but it is also synthesized from other metabolites in the body's cells. In humans, the breakdown of glucose-containing polysaccharides happens in part already during [[chewing]] by means of [[amylase]], which is contained in [[saliva]], as well as by [[maltase]], [[lactase]], and [[sucrase]] on the [[brush border]] of the [[small intestine]]. Glucose is a building block of many carbohydrates and can be split off from them using certain enzymes. [[Glucosidases]], a subgroup of the glycosidases, first catalyze the hydrolysis of long-chain glucose-containing polysaccharides, removing terminal glucose. In turn, disaccharides are mostly degraded by specific glycosidases to glucose. The names of the degrading enzymes are often derived from the particular poly- and disaccharide; inter alia, for the degradation of polysaccharide chains there are amylases (named after amylose, a component of starch), cellulases (named after cellulose), chitinases (named after chitin), and more. Furthermore, for the cleavage of disaccharides, there are maltase, lactase, sucrase, [[trehalase]], and others. In humans, about 70 genes are known that code for glycosidases. They have functions in the digestion and degradation of glycogen, [[sphingolipid]]s, [[mucopolysaccharides]], and poly([[Adenosine diphosphate ribose|ADP-ribose]]). Humans do not produce cellulases, chitinases, or trehalases, but the bacteria in the [[gut microbiota]] do.

In order to get into or out of cell membranes of cells and membranes of cell compartments, glucose requires special transport proteins from the [[major facilitator superfamily]]. In the small intestine (more precisely, in the [[jejunum]]),<ref name="Harper 641">Harold A. Harper: ''Medizinische Biochemie.'' {{In lang|de}}. Springer-Verlag, 2013, {{ISBN|978-3-662-22150-1}}, p.&nbsp;641. {{in lang|de}}</ref> glucose is taken up into the intestinal [[epithelium]] with the help of [[glucose transporter]]s<ref>{{Cite journal |doi=10.1007/s12551-015-0186-2 |pmc=5425736 |pmid=28510148|year=2016 |last1=Navale |first1=A. M. |title=Glucose transporters: Physiological and pathological roles |journal=Biophysical Reviews |volume=8 |issue=1 |pages=5–9 |last2=Paranjape |first2=A. N. }}</ref> via a [[secondary active transport]] mechanism called sodium ion-glucose [[symport]] via [[sodium/glucose cotransporter 1]] (SGLT1).<ref name="Löffler/Petrides 199" /> Further transfer occurs on the [[basolateral]] side of the intestinal epithelial cells via the glucose transporter [[GLUT2]],<ref name="Löffler/Petrides 199" /> as well uptake into [[hepatocyte|liver cells]], kidney cells, cells of the [[Pancreatic islets|islets of Langerhans]], [[neuron]]s, [[astrocyte]]s, and [[tanycyte]]s.<ref>{{Cite journal|doi=10.1007/s00125-014-3451-1|pmid=25421524|year=2015|last1=Thorens|first1=B.|title=GLUT2, glucose sensing and glucose homeostasis|journal=Diabetologia|volume=58|issue=2|pages=221–32|doi-access=free|url=http://doc.rero.ch/record/331705/files/125_2014_Article_3451.pdf|access-date=2024-03-18 March 2024|archive-date=2 December 2023-12-02|archive-url=https://web.archive.org/web/20231202190651/http://doc.rero.ch/record/331705/files/125_2014_Article_3451.pdf|url-status=live}}</ref> Glucose enters the liver via the [[portal vein]] and is stored there as a cellular glycogen.<ref name="Löffler/Petrides 214" /> In the liver cell, it is [[Phosphorylation|phosphorylated]] by [[glucokinase]] at position 6 to form [[glucose 6-phosphate]], which cannot leave the cell. [[Glucose 6-phosphatase]] can convert glucose 6-phosphate back into glucose exclusively in the liver, so the body can maintain a sufficient blood glucose concentration. In other cells, uptake happens by passive transport through one of the 14 GLUT proteins.<ref name="Löffler/Petrides 199" /> In the other cell types, phosphorylation occurs through a [[hexokinase]], whereupon glucose can no longer diffuse out of the cell.

In plants and some [[prokaryote]]s, glucose is a product of [[photosynthesis]].<ref name="photo">{{Cite web|url=http://www.rsc.org/Education/Teachers/Resources/cfb/Photosynthesis.htm|title=Chemistry for Biologists: Photosynthesis|website=www.rsc.org|access-date=5 February 2018-02-05|url-status=live|archive-url=https://web.archive.org/web/20160804060610/http://www.rsc.org/Education/Teachers/Resources/cfb/Photosynthesis.htm|archive-date=4 August 2016-08-04}}</ref> Glucose is also formed by the breakdown of polymeric forms of glucose like [[glycogen]] (in animals and [[mushroom]]s) or starch (in plants). The cleavage of glycogen is termed glycogenolysis, the cleavage of starch is called starch degradation.<ref>{{cite journal |last1= Smith, Alison M. |last2=Zeeman, Samuel C. |last3= Smith, Steven M. |year= 2005 |title= Starch Degradation |journal= Annu. Rev. Plant Biol. |volume= 56 |pages= 73–98 |doi= 10.1146/annurev.arplant.56.032604.144257 |pmid=15862090 }}</ref>

The metabolic pathway that begins with molecules containing two to four carbon atoms (C) and ends in the glucose molecule containing six carbon atoms is called gluconeogenesis and occurs in all living organisms. The smaller starting materials are the result of other metabolic pathways. Ultimately almost all [[biomolecule]]s come from the assimilation of carbon dioxide in plants and microbes during photosynthesis.<ref name=Voet/>{{rp|359}} The free energy of formation of α-{{sm|d}}-glucose is 917.2 kilojoules per mole.<ref name=Voet/>{{rp|59}} In humans, gluconeogenesis occurs in the liver and kidney,<ref name="Szablewski">Leszek Szablewski: ''Glucose Homeostasis and Insulin Resistance.''. Bentham Science Publishers, 2011, {{ISBN|978-1-608-05189-2}}, p.&nbsp;46.</ref> but also in other cell types. In the liver about {{cvt|150|g}} of glycogen are stored, in skeletal muscle about {{cvt|250|g}}.<ref name="Löffler/Petrides 389">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.'' {{In lang|de}}. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;389. {{in lang|de}}</ref> However, the glucose released in muscle cells upon cleavage of the glycogen can not be delivered to the circulation because glucose is phosphorylated by the hexokinase, and a glucose-6-phosphatase is not expressed to remove the phosphate group. Unlike for glucose, there is no transport protein for [[Glucose-6-phosphate dehydrogenase (coenzyme-F420)|glucose-6-phosphate]]. Gluconeogenesis allows the organism to build up glucose from other metabolites, including [[lactic acid|lactate]] or certain [[amino acid]]s, while consuming energy. The renal [[tubular cell]]s can also produce glucose.

Glucose also can be found outside of living organisms in the ambient environment. Glucose concentrations in the atmosphere are detected via collection of samples by aircraft and are known to vary from location to location. For example, glucose concentrations in atmospheric air from inland China range from 0.8 to 20.1 pg/L, whereas east coastal China glucose concentrations range from 10.3 to 142 pg/L.<ref>{{Citecite journal |last1=Wang |first1=Gehui |last2=Kawamura |first2=Kimitaka |last3=Hatakeyama |first3=Shiro |last4=Takami |first4=Akinori |last5=Li |first5=Hong |last6=Wang |first6=Wei|date=2007-04-04 |title=Aircraft Measurement of Organic Aerosols over China|url=http://dx.doi.org/10.1021/es062601h |journal=Environmental Science & Technology |date=May 2007 |volume=41 |issue=9 |pages=3115–3120 |doi=10.1021/es062601h |pmid=17539513 |bibcode=2007EnST...41.3115W|issn=0013-936X|url-access=subscription|access-date=2021-11-09|archive-date=2024-03-18|archive-url=https://web.archive.org/web/20240318213357/https://pubs.acs.org/doi/10.1021/es062601h|url-status=live }}</ref>

In other living organisms, other forms of fermentation can occur. The bacterium ''[[Escherichia coli]]'' can grow on nutrient media containing glucose as the sole carbon source.<ref name=Voet/>{{rp|59}} In some bacteria and, in modified form, also in archaea, glucose is degraded via the [[Entner-Doudoroff pathway]].<ref>{{cite journal | last1 = Entner | first1 = N. | last2 = Doudoroff | first2 = M. | year = 1952 | title = Glucose and gluconic acid oxidation of Pseudomonas saccharophila | journal = [[J Biol Chem]] | volume = 196 | issue = 2| pages = 853–862 | doi = 10.1016/S0021-9258(19)52415-2 | pmid = 12981024 | doi-access = free }}</ref> With Glucose, a mechanism for [[gene regulation]] was discovered in ''E. coli'', the [[catabolite repression]] (formerly known as ''glucose effect'').<ref name="PMID29330542">E.{{cite M.journal | vauthors = Ammar EM, X. Wang X, C.Rao V.CV Rao:| title = ''Regulation of metabolism in Escherichia coli during growth on mixtures of the non-glucose sugars: arabinose, lactose, and xylose.'' In:| journal = ''[[Scientific Reports]].'' Band| volume = 8, Nummer| issue = 1, Januar| 2018,pages = p.&nbsp;609, {{doi| date = January 2018 | pmid = 29330542 | pmc = 5766520 | doi = 10.1038/s41598-017-18704-0}}, PMID| 29330542,bibcode = 2018NatSR...8..609A {{PMC|5766520 url = | issn = }}.</ref>

Use of glucose as an energy source in cells is by either aerobic respiration, anaerobic respiration, or fermentation.<ref name="sil"/> The first step of glycolysis is the [[phosphorylation]] of glucose by a [[hexokinase]] to form [[glucose 6-phosphate]]. The main reason for the immediate phosphorylation of glucose is to prevent its diffusion out of the cell as the charged [[phosphate]] group prevents glucose 6-phosphate from easily crossing the [[cell membrane]].<ref name="sil">{{cite journal|last1=Bonadonna|first1=Riccardo C|last2=Bonora|first2=Enzo|last3=Del Prato|first3=Stefano|last4=Saccomani|first4=Maria|last5=Cobelli|first5=Claudio|last6=Natali|first6=Andrea|last7=Frascerra|first7=Silvia|last8=Pecori|first8=Neda|last9=Ferrannini|first9=Eleuterio|last10=Bier|first10=Dennis|last11=DeFronzo|first11=Ralph A|last12=Gulli|first12=Giovanni|title=Roles of glucose transport and glucose phosphorylation in muscle insulin resistance of NIDDM|journal=Diabetes|date=July 1996|volume=45|issue=7|pages=915–25|doi=10.2337/diab.45.7.915|pmid=8666143|s2cid=219249555|url=http://diabetes.diabetesjournals.org/content/45/7/915.full-text.pdf |archive-url=https://web.archive.org/web/20170306131309/http://diabetes.diabetesjournals.org/content/45/7/915.full-text.pdf |archive-date=6 March 2017-03-06 |url-status=live|access-date=March 5, March 2017}}</ref> Furthermore, addition of the high-energy phosphate group [[Activation#Biochemistry|activates]] glucose for subsequent breakdown in later steps of glycolysis.<ref>{{cite web | url=https://go.drugbank.com/drugs/DB09341 | title=Glucose | access-date=2024-03-18 March 2024 | archive-date=5 December 2023-12-05 | archive-url=https://web.archive.org/web/20231205120936/https://go.drugbank.com/drugs/DB09341 | url-status=live }}</ref> At [[physiological condition]]s, this initial reaction is irreversible.{{medical citation needed|date=March 2024}}

In anaerobic respiration, one glucose molecule produces a net gain of two ATP molecules (four ATP molecules are produced during glycolysis through substrate-level phosphorylation, but two are required by enzymes used during the process).<ref>{{citation | title = Medical Biochemistry at a Glance @Google books | url = https://books.google.com/books?id=9BtxCWxrWRoC&pg=PA52 | year = 2006 | page = 52 | publisher = Blackwell Publishing | isbn = 978-1-4051-1322-9 | url-status = live | archive-url = https://web.archive.org/web/20180223145046/https://books.google.com/books?id=9BtxCWxrWRoC&pg=PA52 | archive-date = 2018-02-23 February 2018 }}</ref> In aerobic respiration, a molecule of glucose is much more profitable in that a maximum net production of 30 or 32 ATP molecules (depending on the organism) is generated.<ref>{{citation|title=Medical Biochemistry at a Glance @Google books|url=https://books.google.com/books?id=9BtxCWxrWRoC&pg=PA50|page=50|year=2006|archive-url=https://web.archive.org/web/20180223145046/https://books.google.com/books?id=9BtxCWxrWRoC&pg=PA50|publisher=Blackwell Publishing|isbn=978-1-4051-1322-9|archive-date=2018-02-23 February 2018|url-status=live}}</ref>

Glucose can also degrade to form carbon dioxide through abiotic means. This has been demonstrated to occur experimentally via oxidation and hydrolysis at 22&nbsp;°C and a pH of 2.5.<ref>{{Citecite journal |last1=Schümann |first1=U. |last2=Gründler |first2=P.|date=1998 |title=Electrochemical degradation of organic substances at PbO2 anodes: Monitoring by continuous CO2 measurements|url=http://dx.doi.org/10.1016/s0043-1354(98)00046-3 |journal=Water Research |date=September 1998 |volume=32 |issue=9 |pages=2835–2842 |doi=10.1016/s0043-1354(98)00046-3|issn=0043-1354|url-access=subscription|access-date=2021-11-09|archive-date=2024-03-18|archive-url=https://web.archive.org/web/20240318215149/https://www.sciencedirect.com/science/article/abs/pii/S0043135498000463?via%3Dihub|url-status=live }}</ref>

[[File:Glucose catabolism intermediates de.png|thumb|upright=1.2|class=skin-invert-image|Diagram showing the possible intermediates in glucose degradation; Metabolic pathways orange: glycolysis, green: Entner-Doudoroff pathway, phosphorylating, yellow: Entner-Doudoroff pathway, non-phosphorylating]]

Glucose is a ubiquitous fuel in [[biology]]. It is used as an energy source in organisms, from bacteria to humans, through either [[aerobic respiration]], [[anaerobic respiration]] (in bacteria), or [[Fermentation (biochemistry)|fermentation]]. Glucose is the human body's key source of energy, through aerobic respiration, providing about 3.75&nbsp;[[kilocalorie]]s (16&nbsp;[[kilojoule]]s) of [[food energy]] per gram.<ref>{{citation | title = Food energy&nbsp;– methods of analysis and conversion factors | chapter-url = http://www.fao.org/docrep/006/Y5022E/y5022e04.htm | chapter = Chapter 3: Calculation of the Energy Content of Foods – Energy Conversion Factors | series = FAO Food and Nutrition Paper 77 | publisher = Food and Agriculture Organization | location = Rome | year = 2003 | isbn = 978-92-5-105014-9 | url-status = live | archive-url = https://web.archive.org/web/20100524003622/http://www.fao.org/DOCREP/006/Y5022E/y5022e04.htm | archive-date = 2010-05-24 May 2010 }}</ref> Breakdown of carbohydrates (e.g., starch) yields [[monosaccharide|mono-]] and [[disaccharide]]s, most of which is glucose. Through [[glycolysis]] and later in the reactions of the [[citric acid cycle]] and [[oxidative phosphorylation]], glucose is [[oxidize]]d to eventually form [[carbon dioxide]] and water, yielding energy mostly in the form of [[adenosine triphosphate|ATP]] (ATP). The insulin reaction, and other mechanisms, regulate the concentration of glucose in the blood. The physiological caloric value of glucose, depending on the source, is 16.2 kilojoules per gram<ref name="Schwedt">Georg Schwedt: ''Zuckersüße Chemie.'' {{In lang|de}}. John Wiley & Sons, 2012, {{ISBN|978-3-527-66001-8}}, p.&nbsp;100 {{in lang|de}}.</ref> or 15.7 kJ/g (3.74 kcal/g).<ref>Schmidt, Lang: ''Physiologie des Menschen'', 30. Auflage. Springer Verlag, 2007, p.&nbsp;907 {{in lang|de}}.</ref> The high availability of carbohydrates from plant biomass has led to a variety of methods during evolution, especially in microorganisms, to utilize glucose for energy and carbon storage. Differences exist in which end product can no longer be used for energy production. The presence of individual genes, and their gene products, the enzymes, determine which reactions are possible. The metabolic pathway of glycolysis is used by almost all living beings. An essential difference in the use of glycolysis is the recovery of [[NADPH]] as a reductant for [[anabolism]] that would otherwise have to be generated indirectly.<ref>{{Cite journal |pmc=1220531 |pmid=10493919 |year=1999 |last1=Dandekar |first1=T. |title=Pathway alignment: Application to the comparative analysis of glycolytic enzymes |journal=The Biochemical Journal |volume=343 |pages=115–124 |last2=Schuster |first2=S. |last3=Snel |first3=B. |last4=Huynen |first4=M. |last5=Bork |first5=P. |doi=10.1042/bj3430115 |issue=1}}</ref>

Glucose and oxygen supply almost all the energy for the [[brain]],<ref>{{cite web |first = Pramod|last = Dash |url =http://neuroscience.uth.tmc.edu/s4/chapter11.html |title=Blood Brain Barrier and Cerebral Metabolism (Section 4, Chapter 11) |work =Neuroscience Online: An Electronic Textbook for the Neurosciences |publisher =Department of Neurobiology and Anatomy – The University of Texas Medical School at Houston |url-status=dead |archive-url=https://web.archive.org/web/20161117104126/http://neuroscience.uth.tmc.edu/s4/chapter11.html |archive-date=2016-11-17 November 2016 }}</ref> so its availability influences [[psychological]] processes. When [[Hypoglycaemia|glucose is low]], psychological processes requiring mental effort (e.g., [[self-control]], effortful decision-making) are impaired.<ref>{{citation | last1 = Fairclough | first1 = Stephen H. | last2 = Houston | first2 = Kim | s2cid = 44500072 | title = A metabolic measure of mental effort | journal = Biol. Psychol. | year = 2004 | volume = 66 | issue = 2 | pages = 177–190 | pmid = 15041139 | doi = 10.1016/j.biopsycho.2003.10.001}}</ref><ref>{{citation | last1 = Gailliot | first1 = Matthew T. | last2 = Baumeister | first2 = Roy F. | last3 = DeWall | first3 = C. Nathan | last4 = Plant | first4 = E. Ashby | last5 = Brewer | first5 = Lauren E. | last6 = Schmeichel | first6 = Brandon J. | last7 = Tice | first7 = Dianne M. | last8 = Maner | first8 = Jon K. | title = Self-Control Relies on Glucose as a Limited Energy Source: Willpower is More than a Metaphor | journal = J. Pers. Soc. Psychol. | year = 2007 | volume = 92 | issue = 2 | pages = 325–336 | pmid = 17279852 | doi = 10.1037/0022-3514.92.2.325 | url = http://www.uky.edu/~njdewa2/gailliotetal07JPSP.pdf | url-status = live | archive-url = https://web.archive.org/web/20170818111037/http://www.uky.edu/~njdewa2/gailliotetal07JPSP.pdf | archive-date = 2017-08-18 August 2017 | citeseerx = 10.1.1.337.3766 | s2cid = 7496171 }}</ref><ref>{{citation | last1 = Gailliot | first1 = Matthew T. | last2 = Baumeister | first2 = Roy F. | title = The Physiology of Willpower: Linking Blood Glucose to Self-Control | journal = Personal. Soc. Psychol. Rev. | year = 2007 | volume = 11 | issue = 4 | pages = 303–327 | doi = 10.1177/1088868307303030 | pmid = 18453466 | citeseerx = 10.1.1.475.9484 | s2cid = 14380313 }}</ref><ref>{{citation | last1 = Masicampo | first1 = E. J. | last2 = Baumeister | first2 = Roy F. | title = Toward a Physiology of Dual-Process Reasoning and Judgment: Lemonade, Willpower, and Expensive Rule-Based Analysis | journal = Psychol. Sci. | year = 2008 | volume = 19 | issue = 3 | pages = 255–60 | doi = 10.1111/j.1467-9280.2008.02077.x | pmid = 18315798| s2cid = 38596025 }}</ref> In the brain, which is dependent on glucose and oxygen as the major source of energy, the glucose concentration is usually 4 to 6&nbsp;mM (5&nbsp;mM equals 90&nbsp;mg/dL),<ref name="Satyanarayana" /> but decreases to 2 to 3&nbsp;mM when fasting.<ref name="Dwyer" /> [[Confusion]] occurs below 1&nbsp;mM and [[coma]] at lower levels.<ref name="Dwyer" />

The glucose in the blood is called [[blood sugar]]. [[Blood sugar level]]slevels are regulated by glucose-binding nerve cells in the [[hypothalamus]].<ref name="Koekkoek">{{Cite journal |doi=10.3389/fnins.2017.00716 |pmc=5742113 |pmid=29311793|year=2017 |last1=Koekkoek |first1=L. L. |title=Glucose-Sensing in the Reward System |journal=Frontiers in Neuroscience |volume=11 |pages=716 |last2=Mul |first2=J. D. |last3=La Fleur |first3=S. E. |doi-access=free }}</ref> In addition, glucose in the brain binds to glucose receptors of the [[reward system]] in the [[nucleus accumbens]].<ref name="Koekkoek" /> The binding of glucose to the sweet receptor on the tongue induces a release of various hormones of energy metabolism, either through glucose or through other sugars, leading to an increased cellular uptake and lower blood sugar levels.<ref name="Tucker">{{Cite journal |doi=10.1016/j.physbeh.2017.09.016 |pmid=28939430 |year=2017 |last1=Tucker |first1=R. M. |title=Do non-nutritive sweeteners influence acute glucose homeostasis in humans? A systematic review |journal=Physiology & Behavior |volume=182 |pages=17–26 |last2=Tan |first2=S. Y. |s2cid=38764657 |url=https://ap01.alma.exlibrisgroup.com/view/delivery/61USOUTHAUS_INST/12149779800001831 |access-date=7 June 2020-06-07 |archive-date=2020-07-29 July 2020 |archive-url=https://web.archive.org/web/20200729195754/https://ap01.alma.exlibrisgroup.com/view/delivery/61USOUTHAUS_INST/12149779800001831 |url-status=dead |url-access=subscription }}</ref> [[Artificial sweetener]]s do not lower blood sugar levels.<ref name="Tucker" />

The blood sugar content of a healthy person in the short-time fasting state, e.g. after overnight fasting, is about 70 to 100&nbsp;mg/dL of blood (4 to 5.5&nbsp;mM). In [[blood plasma]], the measured values are about 10–15% higher. In addition, the values in the [[artery|arterial]] blood are higher than the concentrations in the [[vein|venous]] blood since glucose is absorbed into the tissue during the passage of the [[capillary bed]]. Also in the capillary blood, which is often used for blood sugar determination, the values are sometimes higher than in the venous blood. The glucose content of the blood is regulated by the hormones [[insulin]], [[incretin]] and [[glucagon]].<ref name="Koekkoek" /><ref>{{Cite book |doi=10.1016/B978-0-444-53480-4.00026-6 |pmid=25410233 |year=2014 |last1=La Fleur |first1=S. E. |series=Handbook of Clinical Neurology |volume=126 |pages=341–351 |last2=Fliers |first2=E. |last3=Kalsbeek |first3=A. |title=Diabetes and the Nervous System |chapter=Neuroscience of glucose homeostasis |isbn=978-0-444-53480-4}}.</ref> Insulin lowers the glucose level, glucagon increases it.<ref name="Satyanarayana" /> Furthermore, the hormones [[adrenaline]], [[thyroxine]], [[glucocorticoid]]s, [[somatotropin]] and [[adrenocorticotropin]] lead to an increase in the glucose level.<ref name="Satyanarayana" /> There is also a hormone-independent regulation, which is referred to as [[glucose autoregulation]].<ref>{{Cite journal |doi=10.1002/cphy.c140009 |pmid=25589267 |year=2015 |last1=Bisschop |first1=P. H. |title=Autonomic regulation of hepatic glucose production |journal=Comprehensive Physiology |volume=5 |issue=1 |pages=147–165 |last2=Fliers |first2=E. |last3=Kalsbeek |first3=A.}}</ref> After food intake the blood sugar concentration increases. Values over 180&nbsp;mg/dL in venous whole blood are pathological and are termed [[hyperglycemia]], values below 40&nbsp;mg/dL are termed [[hypoglycaemia]].<ref>W. A. Scherbaum, B. M. Lobnig<!--: ''Abschnittstitel.''.-->, In: Hans-Peter Wolff, Thomas R. Weihrauch: ''Internistische Therapie 2006, 2007''. 16th Edition. Elsevier, 2006, {{ISBN|3-437-23182-0}}, p.&nbsp;927, 985 {{in lang|de}}.</ref> When needed, glucose is released into the bloodstream by glucose-6-phosphatase from glucose-6-phosphate originating from liver and kidney glycogen, thereby regulating the [[homeostasis]] of blood glucose concentration.<ref name="Szablewski" /><ref name="Löffler/Petrides 195" /> In [[ruminant]]s, the blood glucose concentration is lower (60&nbsp;mg/dL in [[cattle]] and 40&nbsp;mg/dL in [[sheep]]), because the carbohydrates are converted more by their gut microbiota into [[short-chain fatty acid]]s.<ref name="Harper">Harold A. Harper: ''Medizinische Biochemie''. Springer-Verlag, 2013, {{ISBN|978-3-662-22150-1}}, p.&nbsp;294.</ref>

As a result of its importance in human health, glucose is an analyte in [[glucose test]]s that are common medical [[blood test]]s.<ref>{{Cite journal |pmid=22872934 |year=2012 |last1=Clarke |first1=S. F. |title=A history of blood glucose meters and their role in self-monitoring of diabetes mellitus |journal=British Journal of Biomedical Science |volume=69 |issue=2 |pages=83–93 |last2=Foster |first2=J. R. |citeseerx=10.1.1.468.2196 |doi=10.1080/09674845.2012.12002443|s2cid=34263228 }}</ref> Eating or fasting prior to taking a blood sample has an effect on analyses for glucose in the blood; a high fasting glucose [[blood sugar]] level may be a sign of [[prediabetes]] or [[diabetes mellitus]].<ref>{{Cite web |url=http://www.diabetes.org/diabetes-basics/diagnosis/ |title=Diagnosing Diabetes and Learning About Prediabetes |website=American Diabetes Association |language=en |access-date=2018-02-20 February 2018 |url-status=live |archive-url=https://web.archive.org/web/20170728020224/http://www.diabetes.org/diabetes-basics/diagnosis/ |archive-date=2017-07-28 July 2017}}</ref>

Other than its direct use as a monomer, glucose can be broken down to synthesize a wide variety of other biomolecules. This is important, as glucose serves both as a primary store of energy and as a source of organic carbon. Glucose can be broken down and converted into [[lipid]]slipids. It is also a precursor for the synthesis of other important molecules such as [[vitamin C]] (ascorbic acid). In living organisms, glucose is converted to several other chemical compounds that are the starting material for various [[metabolic pathway]]s. Among them, all other monosaccharides<ref name="Löffler/Petrides 27">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.'' {{In lang|de}}. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;27. {{in lang|de}}</ref> such as fructose (via the [[polyol pathway]]),<ref name="Löffler/Petrides 199">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.'' {{In lang|de}}. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;199, 200. {{in lang|de}}</ref> mannose (the epimer of glucose at position 2), galactose (the epimer at position 4), fucose, various [[uronic acids]] and the [[amino sugar]]s are produced from glucose.<ref name="Löffler/Petrides 214">Peter C. Heinrich: ''Löffler/Petrides Biochemie und Pathobiochemie.'' {{In lang|de}}. Springer-Verlag, 2014, {{ISBN|978-3-642-17972-3}}, p.&nbsp;214. {{in lang|de}}</ref> In addition to the phosphorylation to glucose-6-phosphate, which is part of the glycolysis, glucose can be oxidized during its degradation to [[glucono-1,5-lactone]]. Glucose is used in some bacteria as a building block in the [[trehalose]] or the [[dextran]] biosynthesis and in animals as a building block of glycogen. Glucose can also be converted from bacterial [[xylose isomerase]] to fructose. In addition, glucose [[metabolite]]s produce all nonessential amino acids, [[sugar alcohol]]s such as [[mannitol]] and [[sorbitol]], [[fatty acid]]s, [[cholesterol]] and [[nucleic acid]]s.<ref name="Löffler/Petrides 27" /> Finally, glucose is used as a building block in the [[glycosylation]] of proteins to [[glycoprotein]]s, [[glycolipid]]s, [[peptidoglycan]]s, [[glycoside]]s and other substances (catalyzed by [[glycosyltransferase]]s) and can be cleaved from them by [[glycosidase]]s.

[[File:Soluţie glucoză 5%.jpg|thumb|right|220px|Glucose, 5% solution for [[Infusion therapy|infusion]]s]]

Individuals with diabetes or other conditions that result in [[hypoglycemia|low blood sugar]] often carry small amounts of sugar in various forms. One sugar commonly used is glucose, often in the form of glucose tablets (glucose pressed into a tablet shape sometimes with one or more other ingredients as a binder), [[hard candy]], or [[sugar packet]].{{clear}}

[[File:Glucose 2.jpg|thumb|GlucoseA tabletssource of glucose]]

Most dietary carbohydrates contain glucose, either as their only building block (as in the polysaccharides starch and glycogen), or together with another monosaccharide (as in the hetero-polysaccharides sucrose and lactose).<ref>{{Cite news|url=https://www.hsph.harvard.edu/nutritionsource/carbohydrates/carbohydrates-and-blood-sugar/|title=Carbohydrates and Blood Sugar|date=5 August 2013-08-05|newspaper=The Nutrition Source|language=en-US|access-date=2017-01-30 January 2017|via=Harvard T.H. Chan School of Public Health|url-status=live|archive-url=https://web.archive.org/web/20170130010758/https://www.hsph.harvard.edu/nutritionsource/carbohydrates/carbohydrates-and-blood-sugar/|archive-date=2017-01-30 January 2017}}</ref> Unbound glucose is one of the main ingredients of honey. Glucose is extremely abundant and has been isolated from a variety of natural sources across the world, including male cones of the coniferous tree ''Wollemia nobilis'' in Rome,<ref>{{Citecite journal |last1=Venditti |first1=Alessandro |last2=Frezza |first2=Claudio |last3=Vincenti |first3=Flaminia |last4=Brodella |first4=Antonia |last5=Sciubba |first5=Fabio |last6=Montesano |first6=Camilla |last7=Franceschin |first7=Marco |last8=Sergi |first8=Manuel |last9=Foddai |first9=Sebastiano |last10=Di Cocco |first10=Maria Enrica |last11=Curini |first11=Roberta |datelast12=2019Delfini |first12=Maurizio |last13=Bianco |first13=Armandodoriano |last14=Serafini |first14=Mauro |title=A syn-ent-labdadiene derivative with a rare spiro-β-lactone function from the male cones of Wollemia nobilis|url=http://dx.doi.org/10.1016/j.phytochem.2018.11.012 |journal=Phytochemistry |date=February 2019 |volume=158 |pages=91–95 |doi=10.1016/j.phytochem.2018.11.012 |pmid=30481664 |bibcode=2019PChem.158...91V|s2cid=53757166|issn=0031-9422|url-access=subscription|access-date=2021-11-11|archive-date=2024-03-18|archive-url=https://web.archive.org/web/20240318215147/https://linkinghub.elsevier.com/retrieve/pii/S0031942218304977|url-status=live }}</ref> the roots of ''Ilex asprella'' plants in China,<ref>{{Citecite journal |last1=Lei |first1=Yu |last2=Shi |first2=She-Po |last3=Song |first3=Yue-Lin |last4=Bi |first4=Dan |last5=Tu |first5=Peng-Fei|date=2014 |title=Triterpene Saponins from the Roots of ''Ilex asprella''|url=http://dx.doi.org/10.1002/cbdv.201300155 |journal=Chemistry & Biodiversity |date=May 2014 |volume=11 |issue=5 |pages=767–775 |doi=10.1002/cbdv.201300155 |pmid=24827686|s2cid=40353516|issn=1612-1872|url-access=subscription|access-date=2021-11-11|archive-date=2024-03-18|archive-url=https://web.archive.org/web/20240318215004/https://onlinelibrary.wiley.com/doi/10.1002/cbdv.201300155|url-status=live }}</ref> and straws from rice in California.<ref>{{Citationcite book |last1doi=Balan|first1=Venkatesh|date=2009|url=http://dx.doi.org/10.1007/978-1-60761-214-8_5|pages=61–77|place=Totowa, NJ|publisher=Humana Press|access-date=2021-11-11|last2=Bals|first2=Bryan|last3=Chundawat|first3=Shishir P. S.|last4=Marshall|first4=Derek|last5=Dale|first5=Bruce E.|title=Biofuels|chapter=Lignocellulosic Biomass Pretreatment Using AFEX |title=Biofuels |series=Methods in Molecular Biology |date=2009 |volume=581 |doipages=10.1007/978-1-60761-214-8_561–77 |pmid=19768616|bibcode=2009biof.book...61B |isbn=978-1-60761-213-1 |url-access vauthors =subscription|archive-date=2024-03-18|archive-url=https://web.archive.org/web/20240318215007/https://link.springer.com/protocol/10.1007/978-1-60761-214-8_5|url-status=live Balan V, Bals B, Chundawat SP, Marshall D, Dale BE }}</ref>

|+ Sugar content of selected common plant foods (in grams per 100&nbsp;g)<ref name="www.nal.usda.gov">{{Cite web|url=https://fdc.nal.usda.gov/index.html|title=FoodData Central|website=fdc.nal.usda.gov|access-date=18 March 2024-03-18|archive-date=3 December 2019-12-03|archive-url=https://web.archive.org/web/20191203185131/https://fdc.nal.usda.gov/index.html|url-status=live}}</ref>

Glucose is produced industrially from starch by [[enzyme|enzymatic]] [[hydrolysis]] using [[glucose amylase]] or by the use of [[acids]]. Enzymatic hydrolysis has largely displaced acid-catalyzed hydrolysis reactions.<ref name="Fellows">P. J. Fellows: ''Food Processing Technology. Woodhead Publishing'', 2016, {{ISBN|978-0-081-00523-1}}, p. 197.</ref> The result is glucose syrup (enzymatically with more than 90% glucose in the dry matter)<ref name="Fellows" /> with an annual worldwide production volume of 20 million tonnes (as of 2011).<ref name="Ullmann 48">Thomas Becker, Dietmar Breithaupt, Horst Werner Doelle, Armin Fiechter, Günther Schlegel, Sakayu Shimizu, Hideaki Yamada: ''Biotechnology'', in: ''Ullmann's Encyclopedia of Industrial Chemistry'', 7th Edition, Wiley-VCH, 2011. {{ISBN|978-3-527-32943-4}}. Volume 6, p. 48.</ref> This is the reason for the former common name "starch sugar". The amylases most often come from ''[[Bacillus licheniformis]]''<ref name="ResSoc">The Amylase Research Society of Japan: ''Handbook of Amylases and Related Enzymes.''. Elsevier, 2014, {{ISBN|978-1-483-29939-6}}, p.&nbsp;195.</ref> or ''[[Bacillus subtilis]]'' (strain MN-385),<ref name="ResSoc" /> which are more thermostable than the originally used enzymes.<ref name="ResSoc" /><ref name="Madsen">{{Cite journal |doi=10.1002/star.19730250906 |title=A New, Heat Stable Bacterial Amylase and its Use in High Temperature Liquefaction |journal=Starch –- Stärke |volume=25 |issue=9 |pages=304–308 |year=1973 |last1=Madsen |first1=G. B. |last2=Norman |first2=B. E. |last3=Slott |first3=S.}}</ref> Starting in 1982, [[pullulanase]]s from ''[[Aspergillus niger]]'' were used in the production of glucose syrup to convert amylopectin to starch (amylose), thereby increasing the yield of glucose.<ref name="Norman">{{Cite journal |doi=10.1002/star.19820341005 |title=A Novel Debranching Enzyme for Application in the Glucose Syrup Industry |journal=Starch –- Stärke |volume=34 |issue=10 |pages=340–346 |year=1982 |last1=Norman |first1=B. E.}}</ref> The reaction is carried out at a pH = 4.6–5.2 and a temperature of 55–60&nbsp;°C.<ref name="Encyclopedia of Food and Health" /> [[Corn syrup]] has between 20% and 95% glucose in the dry matter.<ref>{{cite book | author = James N. BeMiller, Roy L. Whistler | year = 2009 | title = Starch: Chemistry and Technology | series = Food Science and Technology | edition = 3rd | location = New York | publisher = Academic Press | isbn = 978-0-08-092655-1 | url = https://books.google.com/books?isbn=008092655X }}</ref><ref>{{cite book |editor= BeMiller, James N. |editor2=Whistler, Roy L. | year = 2009 | title = Starch: Chemistry and Technology | series = Food Science and Technology | edition = 3rd | location = New York | publisher = Academic Press | isbn = 978-0-08-092655-1 | url = https://books.google.com/books?isbn=008092655X | access-date = 25 November 2016 }}</ref> The Japanese form of the glucose syrup, [[Mizuame]], is made from [[sweet potato]] or [[rice]] starch.<ref>Alan Davidson: ''Oxford Companion to Food'' (1999). "Mizuame", p.&nbsp;510 {{ISBN|0-19-211579-0}}.</ref> [[Maltodextrin]] contains about 20% glucose.

[[File:Relativesweetness.svg|thumb|class=skin-invert-image|Relative sweetness of various sugars in comparison with sucrose<ref>{{cite web

| access-date = 2018-06-28 June 2018

| archive-date = 2011-07-18 July 2011

| date = 2012-05-23 May 2012

In addition, various organic acids can be biotechnologically produced from glucose, for example by fermentation with ''[[Clostridium thermoaceticum]]'' to produce [[acetic acid]], with ''[[Penicillium notatum]]'' for the production of [[araboascorbic acid]], with ''[[Rhizopus delemar]]'' for the production of [[fumaric acid]], with ''[[Aspergillus niger]]'' for the production of [[gluconic acid]], with ''[[Candida brumptii]]'' to produce [[isocitric acid]], with ''[[Aspergillus terreus]]'' for the production of [[itaconic acid]], with ''[[Pseudomonas fluorescens]]'' for the production of [[2-ketogluconic acid]], with ''[[Gluconobacter suboxydans]]'' for the production of [[5-ketogluconic acid]], with ''[[Aspergillus oryzae]]'' for the production of [[kojic acid]], with ''[[Lactobacillus delbrueckii]]'' for the production of [[lactic acid]], with ''[[Lactobacillus brevis]]'' for the production of [[malic acid]], with ''[[Propionibacter shermanii]]'' for the production of [[propionic acid]], with ''[[Pseudomonas aeruginosa]]'' for the production of [[pyruvic acid]] and with ''[[Gluconobacter suboxydans]]'' for the production of [[tartaric acid]].<ref name="Kent">James A. Kent: ''Riegel's Handbook of Industrial Chemistry''. Springer Science & Business Media, 2013, {{ISBN|978-1-475-76431-4}}, p.&nbsp;938.</ref>{{additional citation needed|date=April 2022}} Potent, bioactive natural products like triptolide that inhibit mammalian transcription via inhibition of the XPB subunit of the general transcription factor TFIIH has been recently reported as a glucose conjugate for targeting hypoxic cancer cells with increased glucose transporter expression.<ref>{{cite journal | journal = iScience | title = A Glucose-Triptolide Conjugate Selectively Targets Cancer Cells under Hypoxia | volume = 23 | issue = 9 | year = 2020 |vauthors=Datan E, Minn I, Peng X, He QL, Ahn H, Yu B, Pomper MG, Liu JO | page = 101536 | pmid = 33083765 | doi=10.1016/j.isci.2020.101536| pmc = 7509213 | bibcode = 2020iSci...23j1536D }}</ref> Recently, glucose has been gaining commercial use as a key component of "kits" containing lactic acid and insulin intended to induce hypoglycemia and hyperlactatemia to combat different cancers and infections.<ref>{{Cite journal|last1=Goodwin|first1=Matthew L.|last2=Gladden|first2=L. Bruce|last3=Nijsten|first3=Maarten W. N.|date=3 September 2020-09-03|title=Lactate-Protected Hypoglycemia (LPH)|journal=Frontiers in Neuroscience|volume=14|page=920|doi=10.3389/fnins.2020.00920|pmid=33013305|pmc=7497796|issn=1662-453X|doi-access=free}}</ref>

In the [[Tollens test]], after addition of ammoniacal [[Silver nitrate|AgNO₃]] to the sample solution, glucose reduces Ag⁺ to elemental [[silver]].<ref>B. Tollens: [https://babel.hathitrust.org/cgi/pt?id=uiug.30112025692838;view=1up;seq=535 ''Über ammon-alkalische Silberlösung als Reagens auf Aldehyd''] {{Webarchive|url=https://web.archive.org/web/20220219063751/https://babel.hathitrust.org/cgi/pt?id=uiug.30112025692838;view=1up;seq=535 |date=2022-02-19 February 2022 }}. In ''[[Berichte der Deutschen Chemischen Gesellschaft]]'' (1882), volume 15, p. 1635–1639 (in German).</ref>

In [[Barfoed's test]],<ref name="barfoed">{{Cite journal |doi=10.1007/BF01462957 |title=Ueber die Nachweisung des Traubenzuckers neben Dextrin und verwandten Körpern |language=de |journal=Zeitschrift für Analytische Chemie |volume=12 |pages=27–32 |year=1873 |last1=Barfoed |first1=C. |s2cid=95749674 |url=https://zenodo.org/record/1594255 |access-date=1 July 2019-07-01 |archive-date=2020-07-29 July 2020 |archive-url=https://web.archive.org/web/20200729234027/https://zenodo.org/record/1594255 |url-status=live }}</ref> a solution of dissolved [[copper acetate]], [[sodium acetate]] and acetic acid is added to the solution of the sugar to be tested and subsequently heated in a water bath for a few minutes. Glucose and other monosaccharides rapidly produce a reddish color and reddish brown [[copper(I) oxide]] (Cu₂O).

As a reducing sugar, glucose reacts in the [[Nylander's test]].<ref>Emil Nylander: ''Über alkalische Wismuthlösung als Reagens auf Traubenzucker im Harne'', [[Zeitschrift für physiologische Chemie]]. Volume 8, Issue 3, 1884, p.&nbsp;175–185 [http://www.degruyter.com/dg/viewarticle/j$002fbchm1.1884.8.issue-3$002fbchm1.1884.8.3.175$002fbchm1.1884.8.3.175.xml Abstract]. {{Webarchive|url=https://web.archive.org/web/20150923213720/http://www.degruyter.com/dg/viewarticle/j$002fbchm1.1884.8.issue-3$002fbchm1.1884.8.3.175$002fbchm1.1884.8.3.175.xml |date=2015-09-23 September 2015 }} (in German).</ref>

The enzyme glucose oxidase (GOx) converts glucose into gluconic acid and hydrogen peroxide while consuming oxygen. Another enzyme, peroxidase, catalyzes a chromogenic reaction (Trinder reaction)<ref>{{Cite journal |doi=10.1177/000456326900600108 |title=Determination of Glucose in Blood Using Glucose Oxidase with an Alternative Oxygen Acceptor |journal=Annals of Clinical Biochemistry |volume=6 |pages=24–27 |year=1969 |last1=Trinder |first1=P. |s2cid=58131350 |doi-access=free }}</ref> of [[phenol]] with [[4-Aminoantipyrine|4-aminoantipyrine]] to a purple dye.<ref name="purpuled">{{cite book | chapter-url=https://doi.org/10.1016/bs.pmbts.2019.01.004 | doi=10.1016/bs.pmbts.2019.01.004 | chapter=Fasting blood glucose levels in patients with different types of diseases | title=Glycans and Glycosaminoglycans as Clinical Biomarkers and Therapeutics - Part A | series=Progress in Molecular Biology and Translational Science | date=2019 | volume=162 | pages=277–292 | pmid=30905457 | isbn=978-0-12-817738-9 | vauthors = Zhang Q, Zhao G, Yang N, Zhang L | access-datepmid=2024-03-18 | archive-date=2024-03-18 | archive-url=https://web.archive.org/web/20240318215010/https://www.sciencedirect.com/science/article/abs/pii/S1877117319300158?via%3Dihub | url-status=live30905457 }}</ref>

In particular, for the analysis of complex mixtures containing glucose, e.g. in honey, chromatographic methods such as [[high performance liquid chromatography]] and [[gas chromatography]]<ref name="Galant" /> are often used in combination with [[mass spectrometry]].<ref>{{cite journal | last1 = Sanz | first1 = M. L. | last2 = Sanz | first2 = J. | last3 = Martínez-Castro | first3 = I. | year = 2004| title = Gas chromatographic-mass spectrometric method for the qualitative and quantitative determination of disaccharides and trisaccharides in honey. | journal = [[Journal of Chromatography A]] | volume = 1059 | issue = 1–2| pages = 143–148 | pmid = 15628134 | doi = 10.1016/j.chroma.2004.09.095 }}</ref><ref name="mpg-210190">{{cite web|title=Glucose mass spectrum|periodical=Golm Metabolome Database|url=http://gmd.mpimp-golm.mpg.de/Spectrums/8dee81a1-8d98-4a73-b55d-9de42f10e190.aspx|access-date=4 June 2018-06-04|last=[[Max Planck Institute of Molecular Plant Physiology]] in Golm Database|date=2007-07-19 July 2007|archive-url=https://web.archive.org/web/20180909000409/http://gmd.mpimp-golm.mpg.de/Spectrums/8dee81a1-8d98-4a73-b55d-9de42f10e190.aspx|archive-date=9 September 2018-09-09|url-status=live}}</ref> Taking into account the isotope ratios, it is also possible to reliably detect honey adulteration by added sugars with these methods.<ref>{{cite journal | last1 = Cabañero | first1 = A. I. | last2 = Recio | first2 = J. L. | last3 = Rupérez | first3 = M. | year = 2006| title = Liquid chromatography coupled to isotope ratio mass spectrometry: a new perspective on honey adulteration detection. | journal = [[J Agric Food Chem]] | volume = 54 | issue = 26| pages = 9719–9727 | pmid = 17177492 | doi = 10.1021/jf062067x }}</ref> Derivatization using silylation reagents is commonly used.<ref>{{Cite journal |pmid=24054643|year=2013|last1=Becker|first1=M.|title=Ethoximation-silylation approach for mono- and disaccharide analysis and characterization of their identification parameters by GC/MS|journal=Talanta|volume=115|pages=642–51|last2=Liebner|first2=F.|last3=Rosenau|first3=T.|last4=Potthast|first4=A.|doi=10.1016/j.talanta.2013.05.052}}</ref> Also, the proportions of di- and trisaccharides can be quantified.

Glucose uptake in cells of organisms is measured with [[2-deoxy-D-glucose]] or [[fluorodeoxyglucose]].<ref name="Dwyer">Donard Dwyer: ''Glucose Metabolism in the Brain.''. Academic Press, 2002, {{ISBN|978-0-123-66852-3}}, p.&nbsp;XIII.</ref> (¹⁸F)fluorodeoxyglucose is used as a tracer in [[positron emission tomography]] in oncology and neurology,<ref name="gdch">[[Gesellschaft Deutscher Chemiker]]: [http://www.gdch.de/strukturen/fg/nuklear/posi2.pdf wayback=20100331071121 ''Anlagen zum Positionspapier der Fachgruppe Nuklearchemie''] {{Webarchive|url=https://web.archive.org/web/20100331071121/http://www.gdch.de/strukturen/fg/nuklear/posi2.pdf |date=2010-03-31 March 2010 }}, February 2000.</ref> where it is by far the most commonly used diagnostic agent.<ref>{{Cite journal |doi=10.1155/2014/214748 |pmc=4058687 |pmid=24991541|year=2014 |last1=Maschauer |first1=S. |title=Sweetening pharmaceutical radiochemistry by (18)f-fluoroglycosylation: A short review |journal=BioMed Research International |volume=2014 |pages=1–16 |last2=Prante |first2=O. |doi-access=free }}</ref>

* {{commonsCommons category inline|Glucose}}