The respiration of rat brain mitochondria purified by phase partition. Effects of K+, Mg2+ and Ca2+

Abstract

Highly purified brain mitochondria have been prepared by Na+, NH4+ or K+-containing two-phase systems.K+ stimulated the basal rate of respiration in the three mitochondrial preparations.However, K+ only stimulated the maximal oxidation rate (state 3 respiration rates) in those mitochondria prepared by K+-free (Na+ or NH4+-containing) two-phase systems.The increase in the basal rates of respiration induced by exogenous K+ correlates with the mitochondrial swelling rates.The stimulatory effect of K+ on maximal oxidation rates seems to reflect the K+ depletion of brain mitochondria when prepared by K+-free procedures.