title: Biosynthesis of riboflavin.
abstract: The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate. The imidazole ring of GTP is hydrolytically opened, yielding a 4,5-diaminopyrimidine that is converted to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction, and dephosphorylation. Condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate affords 6,7-dimethyl-8-ribityllumazine. Dismutation of the lumazine derivative yields riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is recycled in the biosynthetic pathway. Two reaction steps in the biosynthetic pathway catalyzed by 3,4-dihydroxy-2-butanone 4-phosphate synthase and riboflavin synthase are mechanistically very complex. The enzymes of the riboflavin pathway are potential targets for antibacterial agents.
authors.affiliation: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, D-85747 Garching, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bacher
authors.forename: S
authors.initials: S
authors.lastname: Eberhardt
authors.forename: W
authors.initials: W
authors.lastname: Eisenreich
authors.forename: M
authors.initials: M
authors.lastname: Fischer
authors.forename: S
authors.initials: S
authors.lastname: Herz
authors.forename: B
authors.initials: B
authors.lastname: Illarionov
authors.forename: K
authors.initials: K
authors.lastname: Kis
authors.forename: G
authors.initials: G
authors.lastname: Richter
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D005285:Fermentation; D006801:Humans; D007700:Kinetics; D012256:Riboflavin / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000737:chemistry; D012258:Riboflavin Synthase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D012258:Riboflavin Synthase; D012256:Riboflavin