Phenazine Methosulfate Uptake fey Rat Liver Mitochondria

Abstract

Calcium stimulated phenazine methosulfate (PMS) accumulation by rat liver mitochondria. PMS uptake required succinate, cyanide, and low O2 tension. The NADH-generating substrate β-hydroxybutyrate did not support PMS accumulation. The rate of PMS uptake was temperature dependent. Amytal, antimycin A, oligomycin, dinitrophenol, and malonate inhibited PMS uptake indicating that electron flow through the respiratory chain was involved. A 100% O2 atmosphere caused PMS efflux from mitochondria which had accumulated PMS anaerobically. It is postulated that PMS is sequestered in mitochondria as a precipitate when reduced by electron transfer. Nonenzymatic oxidation of PMSH by molecular oxygen solubilizes it and efflux from the mitochondria follows.