QUANTITATIVE STUDIES ON ENZYME SYSTEM OF HETEROLACTIC FERMENTATION

II. INTRACELLULAR ACTIVITY OF 6-PHOSPHOGLUCONATE DEHYDROGENASE DURING GLUCOSE FERMENTATION

Abstract

The activity of 6-phosphogluconate dehydrogenase (not decarboxylating) in the sonicate was found to be nearly equal to that of heterolactic fermentation in the washed cells of Leuconostoc mesenteroides B 07, showing a significant participation of the dehydrogenase in the metabolic pathway of the fermentation system in this organism.
It was found that, at pH 5.9 (intracellular pH), activity of the dehydrogenase and the apparent equilibrium constant for this reaction are increased as much as 13- and 120-fold, respectively, at high concentrations of the enzyme protein with a change in quaternary structure.