Corrinoids in anaerobic bacteria

Abstract C₁-metabolizing bacteria were analyzed for their corrinoids. The autotrophic phototrophe Chloroflexus aurantiacus contains predominantly the light-sensitive coenzyme B₁₂. The corrinoid could be teh prostethic group of a methylmalonyl-CoA mutase, which is involved in the CO₂ fixing reaction sequence from proplonyl-CoA to succinyl CoA. Methanobacterium thermoautotrophicum and Sporomusa ovata contain only traces of light-sensitive corrinoids, indicating that the demethylation reaction is favored, if these corrinoids are involved in methyl transfer reactions. The chemical structure of the unique p -cresolyl cobamide is specific for the acetogenic bacterium S. ovata , rather than the corrinoid 'factor III' for methanogenic bacteria.