Oxidative and reductive acetyl CoA/carbon monoxide dehydrogenase pathway inDesulfobacterium autotrophicum

✍ Scribed by Rolf Schauder; Andrea Preuß; Mike Jetten; Georg Fuchs

• Book ID: 104776896
• Publisher: Springer
• Year: 1988
• Tongue: English
• Weight: 776 KB
• Volume: 151
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00444674

✦ Synopsis

It has been proposed that in some anaerobic facultatively autotrophic bacteria the acetyl CoA/CO dehydrogenase pathway is operating both in the reductive and in the oxidative direction, depending on the growth conditions. One of these anaerobes, the Gram-negative sulfate-reducing eubacterium Desulfobacterium autotrophicum, was examined for enzymes of the proposed pathway. All the required enzyme activities were present in sufficient amounts both in autotrophically and in heterotrophically grown cells, provided that the cellular tetrahydropterin rather than tetrahydrofolate was used as cosubstrate in some of the enzyme assays. The question arises whether two sets of enzymes are operating in the reductive and oxidative direction, respectively. The key enzyme of this pathway, CO dehydrogenase, which was reasonably oxygen stable, was analysed by native polyacrylamide gel electrophoresis and anaerobic activity staining. Extracts from heterotrophically grown cells exhibited five enzyme activity bands. Extracts from autotrophically grown cells showed the same pattern but an additional activity band appeared.