Studies on glycogen metabolism in human leukemic cells. I. Glycogen content, glycogen synthetase forms and their metabolic interconversion

Abstract

A decrease in glycogen content and glycogen-synthetase activity was observed in leukemic leucocytes compared to those of normal humans, but the decrease was lesser in chronic myeloid leukemic leucocytes than in those of acute leukemic patients. Incubation of crude leucocyte homogenates at 30 degrees C before assay of the enzyme activity, revealed a conversion of the glycogen-synthetase from the D to the I form. It took place if the enzyme source were enzyme extracts from acute myeloblastic, acute lymphoblastic, chronic lymphocytic, acute menoblastic and undifferenciate leucocytes. The conversion did not occur in crude homogenates from leucocytes of chronic myeloid leukemic patients. ATP-Mg caused a conversion of the glycogen-synthetase I form to the D form in acute myeloblastic, chronic lymphocytic and undifferenciate leukemic leucocytes. This conversion was not observed in chronic myelocytic leukemic leucocytes.