抄録
A cobamide coenzyme-dependent glycerol dehydratase was concomitantly produced with the well-known diol dehydratase in the cells of A. aerogenes ATCC 8724 grown anaerobically on a medium containing glycerol as a sole carbon source. The former enzyme was mainly included in the fraction of 0.2 to 0.4 (NH_4)_2SO_4 saturation, while the latter was predominantly precipitated by 0 to 20% (NH_4)_2SO_4 saturation. The optimum pH of the glycerol dehydratase was approximately 8.0 which was identical with that observed by Pawelkiewicz et al., using another strain of A. aerogenes and different from that of Lactobacillus species reported by Smiley・Sobolov. Its Km values for glycerol and DBC coenzyme were 0.85×10^<-3>M and 3.1×10^<-7>M, respectively. Glycerol served as a carbon source as well as an inducer for both the dehydratases under anaerobic conditions. On the other hand ethanediol and propanediol could not support the bacterial growth, despite of the facts that these compounds were metabolized to unidentified carbonyl compounds after being incorporated into the cells. On aerobic cultivation, all the three compounds were utilized for the growth of the bacteria through oxidative pathways, so could not act as inducers of the cobamide coenzyme dependent dehydratases.
