抄録
1. Both of FMN′ and riboflavinylglucoside mononucleotide of Rhizopus had no effect on the growth of L. casei.
2. The mineral acid hydrolysate of FMN′ and riboflavinylglucoside mononucleotide had growth-promoting effects for L. casei.
3. Riboflavin cyclic diphosphate of Aspergillus oryzae had no effect for the growth of L. casei, but the mineral acid hydrolysate of the new flavin showed a significant growth-promoting effect on L. casei.
4. The absence of growth-promoting activities of FMN′, flavinylglucoside mononucleotide and flavin cyclic diphosphate might reasonably be explained by the presumption that these are stable for the phosphatases of L. casei.
5. FMN of Mucor gave the same growth-promoting effect as the authentic FMN on L. casei.
6. The co-addition of FMN′ to riboflavin or FMN did not affect the growth-response curves of the latter.
7. It was possible to determine the conversion rate of riboflavin into FMN′ in the reaction mixture by microbioassay.
8. Some irregular forms of the cells of L. casei were observed in the 7th subculture containing FMN′.
