STUDIES ON THE SYNTHESIS OF RIBOFLAVIN BY A MUTANT YEAST, SACCHAROMYCES CEREVISIAE

Abstract

The role of purine and pyrimidine compounds and amino acids in the synthesis of riboflavin by a mutant top yeast strain BY2 is studied. Adenine, xanthine, guanine, thymine and uracil increased the riboflavin production while uric acid inhibited it. They did not interfere with growth of the organism, even at higher concns., but showed an optimum concn. for riboflavin stimulation. The inhibitory effect of uric acid and the favorable effect of uracil might suggest the possibility of the existence of different mechanisms for riboflavin synthesis in different organisms. Phenylalanine, tryptophan and serine inhibited growth and riboflavin production. Methionine, glycine and arginine had favorable effects. With glycine and methionine, the increase in riboflavin synthesis was not accompanied by a parallel increase in growth. The active participation of some amino acids in the actual synthesis of riboflavin is indicated.