Abstract
Adenine inhibited riboflavin production of Eremothecium ashbyii increasingly with increasing concentration in non-growing cell medium. Riboflavin production decreased 54% by the addition of the purine at 3×10^<-3>M after incubation for 18h. When adenine at 10^<-3>M was added into non-growing cell medium, S-adenosylhomocysteine accumulated at 1.7×10^<-7>mol in cells after incubation for 12h. On the other hand, in the same experiment, a small amount of S-adenosylmethionine accumulated in cells at the start of the incubation. When methionine at 10^<-2>M was added to the medium, riboflavin production was stimulated and at the same time, a large amount of S-adeno-sylmethionine (1.4×10^<-5>mol) accumulated in the cells after incubation for 12h. Further research indicates that S-adenosylhomocysteine inhibits the riboflavin synthesis and S-adenosylmethionine stimulates the synthesis of this vitamin.
