Doelle H W
J Bacteriol. 1971 Dec;108(3):1284-9. doi: 10.1128/jb.108.3.1284-1289.1971.
Three homofermentative (Lactobacillus plantarum B38, L. plantarum B33, Pediococcus pentosaceus B30) and three heterofermentative (Leuconostoc mesenteroides 39, L. oenos B70, Lactobacillus brevis) lactic acid bacteria were examined for the presence or absence of nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent d- and l-lactate dehydrogenases. Two of the six strains investigated, P. pentosaceus and L. oenos, did not exhibit an NAD-independent enzyme activity capable of reducing dichlorophenol indophenol. The pH optima of the lactic dehydrogenases were determined. The NAD-dependent enzymes from homofermentative strains exhibited optima at pH 7.8 to 8.8, whereas values from 9.0 to 10.0 were noted for these enzymes from heterofermentative organisms. The optima for the NAD-independent enzymes were between 5.8 and 6.6. The apparent Michaelis-Menten constants determined for both NAD and the substrates demonstrated the existence of a greater affinity for d- than l-lactic acid. A comparison of the specific NAD-dependent and NAD-independent lactate dehydrogenase activities revealed a direct correlation of the d/l ratios of these activities with the type of lactic acid produced during the growth of the organism.
对三株同型发酵乳酸菌(植物乳杆菌B38、植物乳杆菌B33、戊糖片球菌B30)和三株异型发酵乳酸菌(肠系膜明串珠菌39、酒类酒球菌B70、短乳杆菌)进行了检测,以确定是否存在烟酰胺腺嘌呤二核苷酸(NAD)依赖性和非NAD依赖性的d-和l-乳酸脱氢酶。在所研究的六株菌株中,戊糖片球菌和酒类酒球菌这两株菌未表现出能够还原二氯酚靛酚的非NAD依赖性酶活性。测定了乳酸脱氢酶的最适pH值。同型发酵菌株的NAD依赖性酶的最适pH值在7.8至8.8之间,而异型发酵菌的这些酶的最适pH值在9.0至10.0之间。非NAD依赖性酶的最适pH值在5.8至6.6之间。对NAD和底物测定的表观米氏常数表明,对d-乳酸的亲和力比对l-乳酸的亲和力更大。对特定的NAD依赖性和非NAD依赖性乳酸脱氢酶活性的比较表明,这些活性的d/l比率与生物体生长过程中产生的乳酸类型直接相关。