Insulin , produced in response to high blood glucose , triggers a separate signal cascade that leads to activation of Phosphoprotein Phosphatase . This Phosphatase catalyzes removal of the regulatory P i from Phosphorylase, Phosphorylase Kinase, and Glycogen Synthase enzymes. Thus insulin antagonizes effects of the cAMP cascade induced by glucagon and epinephrine. These regulatory processes ensure release of phosphorylated glucose from glycogen, for entry into Glycolysis, to provide ATP needed for muscle contraction. Glycogen Storage Diseases are genetic enzyme deficiencies that result in excessive glycogen accumulation within cells.
Additional symptoms depend on the particular enzyme that is deficient.
Some enzymes whose deficiency leads to glycogen accumulation are part of the interconnected pathways shown at right. Copyright 1998-2000, by Joyce J. Diwan. All rights reserved.