So certain molecules that we'll talk about in just a moment can actually act as allosteric activators of glycogen synthase B. And by binding to glycogen synthase B they can actually make it an active molecule. Now to go from glycogen synthase E the fully active molecule that basically stimulates glycogen synthesis into glycogen synthase B the inactive molecule we have to actually use ATP molecules to phosphorylate glycogen synthase A. Now Glycogen synthase A contains several sites where phosphorylation can actually take place and glycogen synthase A also basically responds to a number of different types of protein kinases. But two important protein kinases which basically deactivate glycogen synthase A by phosphorylating it are protein kinase A, PKA and an enzyme known as glycogen synthase kinase or GSK. More specifically, it's glycogen synthase kinase three.