Electrophoretic Characterization of Lactic Dehydrogenases in the Genus Lactobacillus

TLDR: The electrophoretic migration of lactic dehydrogenases of lactobacilli is a useful taxonomic marker for species differentiation and could be detected after electrophoresis by the method of development used.

Abstract: SUMMARY: Crude extracts of 146 strains of different species of Lactobacillus have been submitted to starch gel electrophoresis and the gels developed specifically for lactic dehydrogenases, D or L. NAD-dependent or NAD-independent. Each species contained at least one NAD-dependent lactic dehydro-genase specific for D(-) or for L(+) lactic acid; some species contained both enzymes. For each species there was a strict correlation between the stereo-specificity of the NAD-dependent lactic dehydrogenases found in extracts and the type of lactic acid produced during growth, i.e. D(-), L(+) or DL. The L-lactic dehydrogenases (NAD-dependent) of Lactobacillus casei and L. fermenti were not reversible and consequently could not be detected after electrophoresis. Only those NAD-independent lactic dehydrogenases able to reduce phenazine methosulphate could be detected by the method of development used. Such enzymes were found in extracts of some homo-fermentative lactobacilli. The number and the nature of the lactic dehydrogenases and their respective electrophoretic mobilities are constant within a species. Therefore the electrophoretic migration of lactic dehydrogenases of lactobacilli is a useful taxonomic marker for species differentiation.