On the dehydration of (R)‐lactate in the fermentation of alanine to propionate by Clostridium propionicum

Open Access
Publisher Website
Google Scholar
Abstract
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 α6, α2 and α4, 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.

This publication has 12 references indexed in Scilit: