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Annu Rev Nutr. 2000;20:153-67.

Biosynthesis of vitamin b2 (riboflavin).

Author information

1
Lehrstuhl für Organische Chemie und Biochemie, Lichtenbergstr. 4, D-85747 Garching, Federal Republic of Germany. adelbert.bacher@ch.tum.de

Abstract

The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate as substrates. The imidazole ring of GTP is hydrolytically opened, yielding a 4, 5-diaminopyrimidine which 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. The structure of the biosynthetic enzyme, 6,7-dimethyl-8-ribityllumazine synthase, has been studied in considerable detail.

PMID:
10940330
DOI:
10.1146/annurev.nutr.20.1.153
[Indexed for MEDLINE]

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