Uracil catabolism by Escherichia coli K12S

Experiments designed to elucidate the mechanism of uracil degradation by E. coli K12S showed that in contrast to uracil, dihydrouracil--the postulated intermediate of a reductive mechanism--did not stimulate the growth of bacteria as additional source of nitrogen, nor it was catabolized to ureido carbon dioxide. However, the chromatographic analysis of dihydrouracil metabolic products, revealed the presence of an enzyme converting dihydrouracil to beta-ureidopropionic acid. Results of growth and biochemical studies indicated that barbituric acid--the postulated intermediate of an oxidative pathway--is not involved in uracil degradation.