Question

Which of the following statements is true about the control of muscle glycogen phosphorylase?

(a) It is activated by phosphorylation by an active phosphorylase kinase

(b) It is allosterically activated by ATP

(c) It is allosterically activated by cAMP

(d) Normally it exists in active form

I had been asked this question in an internship interview.

I would like to ask this question from Regulation of Metabolic Pathways in section Principles of Metabolic Regulation: Glucose and Glycogen of Biochemistry

Answer 1

Right choice is (a) It is activated by phosphorylation by an active phosphorylase kinase

To explain I would say: It is allosterically inhibited by ATP. It is partially activated allosterically by AMP. Normally it exists in inactive form.