Decrease of NADH in yeast cells by external ferricyanide reduction.

Ferricyanide reduction catalyzed by vitamin K-3 was accompanied by the decrease in intracellular (NAD(P)H concentration of yeast cells, and the rate of ferricyanide reduction depended on intracellular concentration of NADH rather than NADPH. The addition of glucose to the cell suspensions enhanced both ferricyanide reduction and intracellular NADH concentration. The catalytic action of vitamin K-3 on ferricyanide reduction was observed in the presence of NADH and plasma membrane preparations. As the toxic action of vitamin K-3 on cell growth of yeast was enhanced by addition of ferricyanide, ferricyanide reduction catalyzed by vitamin K-3 may inhibit cell growth by decreasing intracellular NADH concentration.