The allosteric regulation of liver phosphorylase differs from that of the muscle enzyme in two significant aspects:

-AMP doesn not activate liver phosphorylase b

-Liver phosphorylase a is deactivated by the binding of glucose.

The purpose of glycogen degradation in liver is to form glucose for export to other tissues when the blood glucose level is low. hence, liver phosphorylase is responsive to gluose but not to AMP, an indicator of its own metabolic status.