Question

8. The figure on the right is a glycogen phosphorylase (7 pts). Quo), (1) Two hormones regulate glycogen phosphorylase. Explain the effect of each hormone on this enzyme, especially for a) phosphorylation status (phosphorylated vs. non-phosphorylated), and b) the enzyme activity (activated vs. inactivated) of this enzyme (4 pts). Glucagon: Insulin: (2) Glycogen synthase is a processive enzyme. What may be the unique structural feature of glycogen synthase that makes it a processive enzyme? (3 pts)

Answer 1

Glycogen phosphorylase mediates the breakdown of Glycogen to produce Glucose-1-phosphate
It is activated by Phosphorylase kinase
It is inactivated by Protein phosphatase

Phosphorylated form = Active
Unphosphorylated form = Inactive

Insulin inhibits Glycogen phosphorylase.
Glucagon and Epinephrine promote Glycogen phosphorylase.

See the image

Glucagon GLYCOGEN Phosphorylase kinase GLYCOGEN PHOSPHORYLASE Protein phosphatase GLUCOSE-1-PHOSPHATE Insulin