Serine
Serine (abbreviated as Ser or S) encoded by the codons UCU, UCC, UCA, UCG, AGU and AGC is an ɑ-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3 form under biological conditions), a carboxyl group (which is in the deprotonated –COO−
form under biological conditions), and a side chain hydroxyl group, classifying it as a polar amino acid. It is non-essential in humans, meaning the body can synthesize it.
Occurrence
This compound is one of the naturally occurring proteinogenic amino acids. Only the L-stereoisomer appears naturally in proteins. It is not essential to the human diet, since it is synthesized in the body from other metabolites, including glycine. Serine was first obtained from silk protein, a particularly rich source, in 1865. Its name is derived from the Latin for silk, sericum. Serine's structure was established in 1902.
Biosynthesis
The biosynthesis of serine starts with the oxidation of 3-phosphoglycerate (an intermediate from glycolysis) to 3-phosphohydroxypyruvate and NADH by phosphoglycerate dehydrogenase (EC 1.1.1.95). Reductive amination (transamination) of this ketone by phosphoserine transaminase (EC 2.6.1.52) yields 3-phosphoserine (O-phosphoserine) which is hydrolyzed to serine by phosphoserine phosphatase (EC 3.1.3.3).
Persan (grape)
Persan is a red French wine grape variety that is grown primarily in the Savoie region. While the name hints at a Persian origins for the grape, it is most likely native to the Rhône-Alpes region with the name "Persan" being a corruption of the synonym "Princens" which is also the name of a small hamlet by Saint-Jean-de-Maurienne in Savoie which has been noted since the 17th century for the quality of its vineyards.
History
The exact origins of Persan is unknown. The name of the grape lends itself to the theory that it originated in the Middle East and worked its way west via Cyprus. One legend has it that Prince Louis of Savoy had the vine brought to France from Cyprus where he reigned as king in the 15th century. Another theory that Master of Wine Jancis Robinson puts forth is that the name Persan is a corruption of Princens which combined two words from the local dialect meaning prin (or prime) and cens (a fee due to landowners from their vassals). Records indicate in the 17th century there was a vineyard located in the small hamlet of Princens by Saint-Jean-de-Maurienne east of Grenoble that was highly regarded and could have been home to the "Princens" grape that late became known as Persan.
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