Glycogen Metabolism

(Voet & Voet Chapter 17)

1). What is the difference between glycogen and starch (\-amylose and amylopetin?)?

2). Where does the glycogen exist in the body and its physiological function at those organs?

3). Why the body has to use glycogen? Can fat be used instead of glycogen?

4). Catabolism :

a. What is the structural and functional differences between phosphorylase a and b?

b. What is the role of pyridoxal-5-phosphate (PLP) in phosphorylase and its functional difference in amino acid metabolism (e.g. transamination)?

c. What is the reaction intermediate of the phosphoglucomutase reaction?

d. What kind of reaction(s) is/are catalyzed by glycogen debranching enzyme?

5). Anabolism :
  a. How is the free energy supplied to synthesize glycogen from G-1-P?

b. What is the primer for glycogen synthesis?

c. What is the functional difference between glycogen debranching and branching enzymes? And its thermodynamic consideration?

6). How is the glycogen metabolism controlled by allosteric interactions (e.g. ATP, G6P, AMP, glucose, Ca++), covalent modification of enzymes, and enzyme cascades, and what are its mechanisms?

7). What are the mechanism differences between the \-adrenergic and ]-adrenergic functions of the hormonal (e.g. epinephrine) action on glycogen metabolism?

8). What are the roles of phospolipase C and adenylate cyclase in hormonal actions? What kind of second messenger(s) are generated by these enzymes and how do they function?

9). What is the significance of the (1) covalent modification of enzymes and (2) enzyme cascades compare to other regulatory mechanisms?

10). How does Ca++ modulate the glycogen metabolism (function of Calmodulin)?

Practice Problem : Question 5 and 6, Chapter 17 (Voet & Voet, p. 512)

Last modified on 1999.3.21 by K.-J. Hsiao (s)                               [ ]