title: Concerning the biosynthesis of vitamin B12.
mesh_terms: D002250:Carbon Radioisotopes; D002474:Cell-Free System; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D011166:Porphyrins / Q000378:metabolism; D011424:Propionibacterium / Q000378:metabolism; D013329:Structure-Activity Relationship; D014316:Tritium; D014805:Vitamin B 12 / Q000096:biosynthesis*; D014961:X-Ray Diffraction
chemical_list: D002250:Carbon Radioisotopes; D011166:Porphyrins; D014316:Tritium; D014805:Vitamin B 12