1 Department of Pediatrics, Stanford University School of Medicine, 300 Pasteur Drive, Palo Alto, California 94304
Formation of active hepatic phosphorylase is the consequence of a complex series of enzymatic reactions.1 The activation of dephospho-phosphorylase to phosphorylase is catalyzed by a kinase which, in turn, requires activation involving cyclic-3',5'-AMP. The synthesis of this nucleotide is hormonally regulated. In 1959 Hers described three patients with hepatic glycogen storage disease in whom there was diminished phosphorylase activity.2 Activity of phosphorylase was unaffected by either ATP and Mg++ or cyclic-3',5'-AMP. Whether defects in the phosphorylase system can be responsible for glycogen storage remains unresolved.3 Recently, Hug, et al4. described a patient with hepatic glycogen storage disease in whom reduced activity of phosphorylase was demonstrated.