2004 Volume 50 Issue 5 Pages 377-379
The effects of riboflavin on the formation of 6, 7-dimethyl-8-ribityllumazine (DMRL) were examined using the growing cells of a riboflavin, adenine deficient-mutant, Bacillus subtilis. The administration of low concentrations (50-500ng/mL) of riboflavin to the basal medium significantly inhibited the formation of DMRL without any change in growth. Especially, the supplementation of more than 250ng/mL riboflavin completely restricted the formation of DMRL under the experimental conditions. The results clearly indicate that a rigid negative feedback inhibition is operative for the biosynthetic pathway of riboflavin in B. subtilis.