Effect of Uric Acid on Riboflavine Production by Intestinal Coliform Bacteria.

Lau, H. S. (University of Kentucky, Lexington), and R. F. Wiseman. Effect of uric acid on riboflavine production by intestinal coliform bacteria. J. Bacteriol. 87:337-340. 1964.-Cultures of Escherichia coli, Aerobacter aerogenes, and Paracolobactrum species, isolated from human feces and from intestinal contents of rats, were tested for riboflavine synthesis in a chemically defined medium. Riboflavine was assayed by a fluorometric method and by microbiological assay. When uric acid was added to the synthetic medium at levels ranging from 10 to 750 mug/ml, it inhibited the production of riboflavine, but did not affect the growth of the bacteria. As the amount of uric acid in the medium was increased from 10 to 750 mug, there was a corresponding decrease in the amount of riboflavine produced. Some disappearance of uric acid was observed in the cultures. These results suggest that uric acid, or its degradation products, may have acted as an antimetabolite or an enzyme inactivator in the biosynthesis of riboflavine.