Glycogen synthesis in bacteria

ADP-Glucose Is the Substrate for Starch Synthesis in Plant Plastids and for Glycogen Synthesis in Bacteria... 

Synthesis of the 1,4-a-D-glucosidic bond in starch is catalyzed by starch synthase (E.C. 2.4.1.21 ADP-glucose 1,4-a-D-glucan 4-a-glucosyltransferase reaction 2) and was first reported by Leloir (13,14). Similar reactions are seen for glycogen synthesis in bacteria and cyanobacteria (15), and the enzyme is termed glycogen synthase (also E.C. 2.4.1.21). 

Preiss J, Romeo T. Molecular biology and regulatory aspects of glycogen synthesis in bacteria. Prog. Nucleic Acid Res. Molec. 

Biochemistry and Molecular Biology of Glycogen Synthesis in Bacteria and Mammals and Starch Synthesis in Plants... 

The reactions of starch synthesis 1, 7, and 8 are essentially similar to those of glycogen synthesis in bacteria but the structure of the ultimate polysaccharides formed are different. 

Because of its roles in the synthesis of glycogen, in isomerization of hexose phosphates, and as a precursor for numerous biosynthetic intermediates, UDP-glucose is regarded as a central hexose derivative in mammalian metabolism. In bacteria and plants, both ADP-glucose (production of storage polysaccharide) and UDP-glucose (sugar interconversions and biosynthesis) play important roles as precursors. 

In contrast to animals, bacteria such as E. coli synthesize glycogen via ADP-glucose rather than UDP-glucose.88 ADP-glucose is also the glucosyl donor for synthesis of starch in plants. The first step in the biosynthesis (Eq. 20-18) is catalyzed by the enzyme ADP-glucose pyrophosphorylase (named for the reverse reaction). 

Maltodextrin phosphorylase and glycogen phosphorylase (Reaction (6)) occur in many bacteria and catalyzes the synthesis as well as the phosphorolysis of a-4-glucosidic linkages present in glycogen or starch. Maltodextrin phosphorylase however is only induced in the presence of maltodextrins, and for the microorganisms studied, glycogen phosphorylase activity is insufficient to account for their rate of glycogen accumulation. Moreover,... 

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