Biosynthesis of riboflavin

Abstract

The 2,5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5′-phosphate deaminase was partially purified from cell extracts of Candida guilliermondii ATCC 9058. The enzyme requires Mg²⁺ for activity. Maximal activity was observed at pH 7.3. The enzyme converts its substrate, 2,5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5′-phosphate, to 2,5-diamino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5′-phosphate. This labile compound was treated with diacetyl and the resulting 6,7-dimethyl-8-ribityllumazine 5′-phosphate was identified by comparison with a synthetic sample.