title: Multiple forms of lactate dehydrogenase in Staphylococcus aureus.
abstract: Activities for nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent forms of lactate dehydrogenase (LDH) were measured in cell-free extracts of Staphylococcus aureus strain PS 6 for the d and l isomers of lactate. Data obtained for the NAD-dependent lactate dehydrogenases indicate that oxidation of both isomers of lactate is due to both an l-lactate-specific LDH and a lactate racemase. After acrylamide gel electrophoresis, two bands exhibiting LDH activity were detected in crude or in partially purified cell-free extracts. The fast band exhibited LDH activity that was not NAD-dependent for both isomers of lactate, whereas, the slow band had very high NAD-dependent LDH activity for the l isomer but just detectable activity or the d isomer. Both bands appeared when d-lactate was used as the substrate, but only the slow band was formed when l-lactate was the substrate. NAD-dependent LDH, in apparent association with a nonspecific tetrazolium-reducing protein, is responsible for the production of the slow band.
mesh_terms: D002474:Cell-Free System; D004586:Electrophoresis; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007535:Isomerases / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000302:isolation & purification*; D009243:NAD / Q000378:metabolism; D011773:Pyruvates / Q000032:analysis; D013210:Staphylococcus / Q000201:enzymology* / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D011773:Pyruvates; D009243:NAD; D007770:L-Lactate Dehydrogenase; D007535:Isomerases