Biosynthesis of vitamin B12: identity of fragment extruded during ring contraction to the corrin macrocycle.
Incorporation experiments with labeled sirohydrochlorin and trimethylisobacteriochlorin demonstrate that ring contraction in vivo to the corrin macrocycle of vitamin B12 liberates acetic acid. The C-20 atom of the precursors becomes the acetate carboxyl carbon.
D000085:Acetates / Q000096:biosynthesis; D001429:Bacteriochlorophylls / Q000378:metabolism; D002474:Cell-Free System; D055598:Chemical Phenomena; D002621:Chemistry; D045728:Corrinoids; D011424:Propionibacterium / Q000378:metabolism; D014805:Vitamin B 12 / Q000096:biosynthesis* / Q000378:metabolism
D000085:Acetates; D001429:Bacteriochlorophylls; D045728:Corrinoids; D014805:Vitamin B 12