GYS

GYS may refer to:

GYS (company)

Founded in 1964, in Laval, GYS is a French family-owned industrial group that engineers and manufactures three portfolio of products:

Although GYS is headquartered in Laval, Mayenne - about 280 km west of Paris - the industrial group has R&D centers, factories and commercial subsidiaries in France, Germany, UK, India and China.

Group history

1964 : In France, in 1963, EDF decided to change the electrical voltage from 110 V to 230 V. Mr. Stephany created GYS in 1964 with the purpose of manufacturing auto-transformers on behalf of EDF for the west part of France. .

1970 : In the early 1970s, GYS expanded its product range with car battery chargers. The company first engineered and manufactured car battery chargers in 6 V, then in 6 V/12 V and finally in 6 V/12 V/24 V. In the late 1970s, an additional product expansion is realized with the manufacturing of GYS' first welding machine.

Glycogen synthase

Glycogen synthase (UDP-glucose-glycogen glucosyltransferase) is an enzyme involved in converting glucose to glycogen. It takes short polymers of glucose and converts them into long polymers of glycogen.

It is a glycosyltransferase enzyme (EC 2.4.1.11) that catalyses the reaction of UDP-glucose and (1,4-α-D-glucosyl)_n to yield UDP and (1,4-α-D-glucosyl)_n+1.

In other words, this enzyme converts excess glucose residues one by one into a polymeric chain for storage as glycogen. Glycogen synthase concentration is highest in the bloodstream 30 to 60 minutes following intense exercise. It is a key enzyme in glycogenesis.

Structure

Much research has been done on glycogen degradation through studying the structure and function of glycogen phosphorylase, the key regulatory enzyme of glycogen degradation. On the other hand, much less is known about the structure of glycogen synthase, the key regulatory enzyme of glycogen synthesis. The crystal structure of glycogen synthase from Agrobacterium tumefaciens, however, has been determined at 2.3 A resolution. In its asymmetric form, glycogen synthase is found as a dimer, whose monomers are composed of two Rossmann-fold domains. This structural property, among others, is shared with related enzymes, such as glycogen phosphorylase and other glycosyltransferases of the GT-B superfamily. Nonetheless, a more recent characterization of the Saccharomyces cerevisiae (yeast) glycogen synthase crystal structure reveals that the dimers may actually interact to form a tetramer. Specifically, The inter-subunit interactions are mediated by the α15/16 helix pairs, forming allosteric sites between subunits in one combination of dimers and active sites between subunits in the other combination of dimers. Since the structure of eukaryotic glycogen synthase is highly conserved among species, glycogen synthase likely forms a tetramer in humans as well.