Question

How do the structures of glycogen synthase and glycogen phosphorylase relate to their regulation?

Answer 1

The structural property of both glycogen synthase and glycogen phosphorylase, that is similar and they share is that both of them are dimers.

The binding of protein phosphtase to the binding site of glycogen synthase leads to activation of the enzyme whereas the binding of protein kinase to the binding site of glycogen synthase leads to the inhibition of the enzyme activity.

Similarly, the binding of protein phoshatase to the binding site of glycogen phosphorylase leads to the inhibition of the enzyme whereas the binding of phosphorylase kinase to the binding site of glycogen phosphorylase activates the enzyme.

So the activity of the two enzymes is regulated by the action of kinase and phosphatase towards the binding sites of the two enzymes and the two enzymes work in the opposite direction.