6,7-Dimethyl-8-ribityllumazine → Riboflavin

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Reaction Steps

Guanosine triphosphate (GTP) is converted by GTP cyclohydrolase II (rib 1 gene product) into 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5-phosphate. This compound is subsequently reduced by the rib 7 gene product to 2,5-diaminoribitylamino-2,4(1H,3H)-pyrimidine 5-phosphate and then deaminated by the rib 2 gene product to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. Subsequently, in a reaction catalyzed by the rib 4 gene product, the C4 compound DBP is added on to result in 6,7-dimethyl-8-ribitvllumazine (DMRL), from which riboflavin is produced in the reaction catalyzed by the rib 5 gene product. The C4 compound DBP (L-3,4-dihydroxy-2-butanone 4-phosphate) is formed from D-ribulose 5-phosphate in a reaction catalyzed by the rib 3 gene product.

Provenance & Evidence