Über Zwischenprodukte der Riboflavin-Biosynthese bei Saccharomyces cerevisiae

Abstract

Using various riboflavin deficient mutants of S. cerevisiae, we have found two intermediates of the riboflavin biosynthesis. 6.7-Dimethyl-8-ribityl-lumazine was isolated from the culture fluid of two mutants. The formation of 4-ribitylamino-5-amino-uracil by two other mutants was proved by trapping the product with glyoxal or diacetyl, leading to the formation of 8-ribityl-lumazine or 6,7-dimethyl-8-ribityl-lumazine and riboflavin respectively. These mutants were able to grow in riboflavin free medium supplemented with diacetyl. 6,7-Dimethyl-8-ribityl-lumazine promoted the growth of adequately blocked mutants.