title: Biosynthesis of vitamin B12: nature of the volatile fragment generated during formation of the corrin ring system.
abstract: It is shown with the help of radiolabeled substrates that biological formation of the corrin ligand system of cobyrinic acid is linked with the release of an equivalent of acetic acid from a hydroporphinoid precursor in which the C-20 atom has undergone methylation prior to its excision from the macrocycle.
mesh_terms: D000085:Acetates / Q000096:biosynthesis; D002474:Cell-Free System; D055598:Chemical Phenomena; D002621:Chemistry; D011162:Porphobilinogen / Q000378:metabolism; D011424:Propionibacterium / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000096:biosynthesis*
chemical_list: D000085:Acetates; C010895:cobyrinic acid; D011162:Porphobilinogen; D014805:Vitamin B 12