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

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.