Question

Glycogen phosphorylase is found in the cytosol of muscle cells. Glycogen phosphorylase is responsible for catabolizing glycogen into glucose during periods of intense muscular activity.

Without glycogen phosphorylase, muscle cells would be able to catabolize glycogen; however, the process would be time-inefficient, and the energy required and expended would be taxing on the cell. The presence of glycogen phosphorylase speeds up the catabolic reaction.

Glycogen phosphorylase is only activated after it has been phosphorylated. The hormone epinephrine signals the muscle cell to begin the chemical process of adding a phosphate group to the enzyme so that it can catabolize glycogen. Based on the way glycogen is catabolized by glycogen phosphorylase, which of the following BEST describes the mechanism of enzyme-mediated control used in this process?

A. Control of glycogen metabolism involves allosteric activation and inhibition of glycogen phosphorylase.
B. Control of glycogen metabolism involves inhibitors binding to glycogen phosphorylase
C. Control of glycogen metabolism involves a simple enzyme-substrate interaction between glycogen and glycogen phosphorylase
D. Control of glycogen metabolism involves non-competitive inhibitors acting on glycogen phosphorylase

I'm thinking that based on the fact glycogen phosphorylase is activated by phosphorylation (addition of a po3), then the enzyme's activity must be controlled by an inhibitor of some sorts. I'm not entirely sure

Answer 1

Nevermind, I confused allosteric activation with noncompetitive inhibition. The answer should just be A.