Solubility behaviour of phosphofructokinase from haemolysate of erythrocytes, reticulocytes and bone marrow cells in poly (ethylene glycol) solutions.

The precipitation profiles of phospofructokinase obtained by addition of poly(ethylene glycol) to haemolysates of erythrocytes, reticulocytes and bone marrow are displaced towards higher polymer concentrations when the pH decreases from 6 to 5 or increases from 6 to 8. In the pH range 5 to 8, the concentration of polymer required to provide any level of precipitation follows the order erythrocytic less than reticulocytic less than bone marrow phosphofructokinase. The precipitation of erythrocytic and reticulocytic phosphofructokinase is enhanced by the presence of F6P and ATP. No effect is observed for bone marrow phosphofructokinase. These results are consistent with an isoenzymatic variation of phosphofructokinase in erythrocytes, reticulocytes and bone marrow cells.