Properties and activities of phosphoribomutase in the human leukemic cells

1. The activities and properties of phosphoribomutase were determined in human leukemic leukocytes and normal polymorphonuclear leukocytes. 2. Leukemic leukocytes had markedly increased phosphoribomutase activity. 3. The Km value of leukemic cells to R-1-P was identical to normal cells. However, the Km value to glucose-1-6-diphosphate in leukemic cells had been shown to be low. 4. Inhibition rates by 2-3-DPG and Pi were lower in leukemic cells. 5. Leukemic cells enzyme was unstable by heating. 6. There were no significant differences in isoelectric points between normal cells and leukemic cells.