Glycogen Metabolism1. Glycogenesis2. Glycogenolysis3. Regulation Of Glycogen Metabolism4. Glycogen Storage Disease

GLYCOGENESIS

1- Synthesis of UDP-glucose2-Glycogen synthesis by glycogen synthase3-Formation of branches in glycogen

1- Synthesis of UDP-glucose

2-Glycogen synthesis by Glycogensynthase

3- Formation of branches in glycogen

amylo-(1,4 S 1,6)-transglycosylase

Glycogen Breakdown

A. Glycogen Phosphorylase

B. Phosphoglucomutase

C. Glycogen Debranching Enzyme

Gycogenolysis

• Glycogen phosphorylase is a dimer of identical 842-residue (97-kD) subunits

that catalyzes the controlling step in glycogen breakdown.

• It is regulated both by allosteric interactions and by covalent modification.

• The enzyme-catalyzed modification/demodification process yields two forms of

phosphorylase: phosphorylase a, which has a phosphoryl group esterified

to Ser 14 in each of its subunits, and phosphorylase b, which lacks these

phosphoryl groups.

1- Glycogen Phosphorylase

2. Phosphoglucomutase

Glycogen Debranching Enzyme

REGULATION OF GLYCOGEN METABOLISM

1. Allosteric Regulation

2- Hormonal Regulation

3- Regulation by Ca++

GLYCOGEN STORAGE DISEASES