All are True for CAMP-Dependent Protein Kinase EXCEPT

Question

All are true for cAMP-dependent protein kinase EXCEPT:
A) also known as PKA.
B) phosphorylase kinase is a substrate.
C) consists of a pair of catalytic subunits.
D) two regulatory subunits block catalytic activity without cAMP binding.
E) phosphorylates glycogen phosphorylase.

Accepted Answer

Phosphorylase kinase, not glycogen phosphorylase, is a substrate for cAMP-dependent protein kinase (PKA). PKA phosphorylates many proteins but not glycogen phosphorylase directly; it phosphorylates and activates phosphorylase kinase, which in turn phosphorylates glycogen phosphorylase.