Schweiger G, Buckel W
FEBS Lett. 1984 Jun 4;171(1):79-84. doi: 10.1016/0014-5793(84)80463-9.
All the enzymes of the pathway of (S)-alanine fermentation to acetate and propionate were detected in cell-free extracts of Clostridium propionicum . Among these (S)-glutamate dehydrogenase (NAD), (R)-lactate dehydrogenase (NAD) and propionate CoA-transferase were purified to apparent homogeneity. Their structures were presumably alpha 6, alpha 2 and alpha 4, respectively. The latter enzyme was specific for short-chain monocarboxylic acids with a pronounced preference for (R)-lactate over the (S)-enantiomer. The key step of the pathway, the dehydration of (R)-lactate required acetyl phosphate and CoASH under anaerobic conditions. It was inhibited by hydroxylamine, arsenate, azide (1 mM each) or by 0.1 mM 2,4-dinitrophenol. Thus it closely resembled the dehydration of (R)-2-hydroxyglutarate in Acidaminococcus fermentans , although an activation was not necessary.
在丙酸梭菌的无细胞提取物中检测到了（S）-丙氨酸发酵生成乙酸盐和丙酸盐途径中的所有酶。其中，（S）-谷氨酸脱氢酶（NAD）、（R）-乳酸脱氢酶（NAD）和丙酸盐辅酶A转移酶被纯化至表观均一。它们的结构推测分别为α6、α2和α4。后一种酶对短链单羧酸具有特异性，对（R）-乳酸的偏好明显高于（S）-对映体。该途径的关键步骤，即（R）-乳酸的脱水反应在厌氧条件下需要乙酰磷酸和辅酶A。它受到羟胺、砷酸盐、叠氮化物（各1 mM）或0.1 mM 2,4-二硝基苯酚的抑制。因此，它与发酵氨基酸球菌中（R）-2-羟基戊二酸的脱水反应非常相似，尽管不需要激活。
