Glycogen metabolism

Описание: Glycogen metabolism- This lecture explains about the glycogen synthesis and glycogen breakdown in cell.
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The overall reaction for the breakdown of glycogen to glucose-1-phosphate is:

glycogen(n residues) + Pi is in equilibrium with glycogen(n-1 residues) + glucose-1-phosphate

Here, glycogen phosphorylase cleaves the bond linking a terminal glucose residue to a glycogen branch by substitution of a phosphoryl group for the α[1→4] linkage. Glucose residues are phosphorolysed from branches of glycogen until four residues before a glucose that is branched with a α[1→6] linkage. Glycogen debranching enzyme then transfers three of the remaining four glucose units to the end of another glycogen branch. This exposes the α[1→6] branching point, which is hydrolysed by α[1→6] glucosidase, removing the final glucose residue of the branch as a molecule of glucose and eliminating the branch. This is the only case in which a glycogen metabolite is not glucose-1-phosphate. The glucose is concomitantly phosphorylated to glucose-1-phosphate by hexokinase. Glucose-1-phosphate is converted to glucose-6-phosphate by the enzyme phosphoglucomutase.
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.

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. Its presence in the bloodstream is highest in the 30 to 60 minutes[2] following intense exercise. It is a key enzyme in glycogenesis. Source of the article published in description is Wikipedia. I am sharing their material. © by original content developers of Wikipedia.
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