Rapid, Respiration-independent Binding of Alkali Metal Cations by Rat Liver Mitochondria

摘要: Abstract When rat liver mitochondria suspended in salt-free 0.25 m sucrose solution are mixed with weakly buffered solutions of NaCl, the suspending medium undergoes very rapid acidification. This reaction was found to proceed absence electron transport. The amount acid produced increased increasing NaCl concentration, initial pH, and concentration mitochondria. H+ released exceeded 35 nmoles per mg protein. Similar effects were given when replaced by chlorides other univalent cations; relative activities Li+ g NH4+ choline+ Na+ K+ Rb+ Tris+. acidification requires presence a salt; as little 2.5 mm measurable release. Acid-base titration curves intact increasingly displaced side concentration. Flame photometry isolated after mixing (or LiCl) showed that Li+) bound an equimolar released. interaction not intrinsically affected 2,4-dinitrophenol, gramicidin, or valinomycin. During binding release H+, endogenous Mg++ lost from valinomycin permeability-inducing agents. These observations on alkali metal cations appear provide possible basis for their action Ca++:O accumulation ratio during energy-linked Ca++ uptake superstoichiometric levels.