Glucose-06-phosphate-dehydrogenase from sea mussel hepatopancreas

Abstract

Glucose-06-phosphate-dehydrogenase activity was found in the subcellular components of the sea mussel Mytilus edulis L., most of it, 99.42%, in the supernatant (cytosolic) fraction. A mitochondrial form of glucose-06-phosphate-dehydrogenase of diverse exhibiting coenzyme specificity towards NAD+ and NADP+ was solubilized. The inhibitory effect of some phosphate compounds on cytosolic glucose-06-phosphate-dehydrogenase activity, has been studied. The inhibition constants for fructose-1,6-diphosphate, and phosphoenol pyruvate in relation to the glucose-06-phosphate substrate, have been determined. Cytosolic enzyme activity dependence on pH has been tested with and without fructose diphosphate. Lastly, the inhibition rate of various fructose diphosphate concentrations against constant substrate concentrations have been determined, as well as the inhibitory effects by the simultaneous action of fructose diphosphate and NADPH.