Quantitative Studies on Glycolytic Enzymes in Lactobacillus Plantarum

In order to clarify the mechanism of racemic lactate formation in Lactobacillus plantarum, the intracellular activities of NAD-linked D- and L-lactate dehydrogenases were estimated. Both enzymes were separated from each other and purified about 90-fold by ammonium sulfate fractionation and DEAE cellulose chromatography. Basal properties of these purified enzymes were examined. These enzymes were distinguishable by their substrate specificity, heat stability and oxamate inhibition. From the activities of both enzymes in a sonic extract, their respective intracellular activities were calculated by correcting these values for the intracellular conditions which have been reported previously. It was found that both of the enzymes operated with equal activity in glucose-metabolizing washed cells.