Enzymes of Glycogen Metabolism in White Blood Cells. I. Glycogen Phosphorylase in Normal and Leukemic Human Leukocytes.

Glycogen phosphorylase has been assayed in normal leukocytes and in those ob tained from patients with chronic granulocytic and chronic lymphocytic leukemia. Assay was performed in the direction of both glycogen degradation and glycogen syn thesis with and without adenylic acid. The results indicate that (a) a major portion of phosphorylase activity exists in the active or a form as evidenced by 30-70 per cent activity in the absence of adenosine-S'-phosphate, (6) wide variations in activity were noted in leukocytes from different donors, (c) leukocyte phosphorylase activity in leukemic cells did not differ significantly from the normal. Some of the properties of leukocyt9 glycogen phosphorylase and its relation to phosphorylase from liver and muscle are discussed.