ON THE EFFECTS OF ZINC AND CADMIUM IONS ON THE NEW FLAVIN PHOSPHATE-PRODUCING ACTIVITY OF RHIZOPUS JAVANICUS

Abstract

1. By addition of 10^-4 to 5×10^-3M Zn²⁺ in the reaction mixture, FMN′-producing activity of the dry mycelia of Rh. javanicus was inhibited.
2. Addition of 10^-4 to 5×10^-3M Zn²⁺ to the culture medium stimulated the growth and depressed the acid production.
3. The zinc-grown mycelia exhibited lower FMN′-forming activity.
4. Co-addition of riboflavin to Zn²⁺ reduced the effects caused by the sole addition of Zn²⁺.
5. By addition of 10^-6 to 5×10^-5M Cd²⁺ in the reaction mixture, FMN′-producing activity of the dry mycelia of the mold was inhibited, but the inhibition was reduced when incubation was prolonged.
6. Addition of 10^-6 to 5×10^-5M Cd²⁺ to the culture medium markedly inhibited the growth, without marked inhibition of acid production.
7. The cadmium-grown mycelia exhibited higher FMN′-producing activity than the control.
8. Co-addition of riboflavin with Cd²⁺ failed to reduce the effects caused by the sole addition of Cd²⁺.
9. From these evidences, it was assumed that FMN′ or FMN′-forming enzyme might play a role of regulator between growth and acid production.