title: Nuclear magnetic resonance studies of the biosynthesis of vitamin B12. The origin of the methyl groups on the corrin ring.
mesh_terms: D002247:Carbon Isotopes; D055598:Chemical Phenomena; D002621:Chemistry; D007536:Isomerism; D007982:Levulinic Acids / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000378:metabolism; D011166:Porphyrins / Q000096:biosynthesis; D011422:Propionates / Q000032:analysis; D011424:Propionibacterium / Q000254:growth & development / Q000378:metabolism*; D011522:Protons; D014805:Vitamin B 12 / Q000096:biosynthesis* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D002247:Carbon Isotopes; D007982:Levulinic Acids; D011166:Porphyrins; D011422:Propionates; D011522:Protons; D008715:Methionine; D014805:Vitamin B 12