SOLUBILIZATION OF PHOSPHOFRUCTOKINASE FROM THE PARTICULATE FRACTION OF CHICKEN MUSCLE

The particulate fraction of chicken breast muscle (pH 6.5–6.7) contained 99% of the phosphofructokinase (PFK) activity. A dramatic shift from the particulate to the soluble form occurred at pH 7.05±0.10. ATP and MgATP were effective solubilizers of PFK at pH 6.7. ADP appeared to be converted to a solubilizer of PFK after incubation in the crude system. Cyclic AMP and AMP were not effective solubilizers at pH 6.7. The solubilization by ATP was dependent on the concentration of the nucleotide and could be prevented by lowering the pH to 6.0. Pyruvate, fructose-6-phosphate, glucose-6-phosphate, fructose-1, 6-diphosphate, glucose-1, 6-diphosphate, 2-phosphoglycerate, 2, 3-diphosphoglycerate, 3-phosphoglycerate and pyrophosphate were not effective solubilizers at pH 6.7 at the concentrations tested.