Glycogen phosphorylase requires -

Ans. is 4b' i.e., Pvridoxal phosphate o Glycogenolysis occurs primarily by phosphorolytic breaking of a-l,4-glycosidic bonds of glycogen. The key enzyme responsible for glycogenolysis is glycogen phosphorylase which catalyses stepwize phosphorolytic removal of glucose as glucose-1-phosphate, from glycogen.o Pvridoxal phosphate is essential cofactor in this reaction; it is covalently bound to glycogen phosphorylase.