[Effect of lactate and glycolytic intermediates on muscle creatine kinase].

Inhibition of rabbit muscle creatine kinase by lactate, glucose-6-phosphate and PEP occurs immediately and depends on the concentration of the effectors and enzyme properties. Desensitization of creatine kinase to these effectors is described. Partial desensitization to G-6-P and lactate occurs after the enzyme preincubation with dithiothreitol. A complete loss of sensitivity to lactate and a significant loss of sensitivity to G-6-P and PEP occurs after the enzyme storage at -15 degrees during several weeks. The data obtained support our previously made assumption on the allosteric regulation of the MM isoenzyme of creatine kinase.