The ATPase inhibitor protein in oxidative phosphorylation The rate-limiting factor to phosphorylation in submitochondrial particles

摘要: 1. Purified luciferase and luciferin were used to study the time course of phosphorylation in submitochondrial particles. The light emitted was detected by a single-photon counter, using multichannel analyser, results analysed an 'on-line' digital computer. 2. Using NADH as substrate, showed, general, four phases. These (i) period increasing rate ('lag'); (ii) constant (positive) rate; (iii) zero net (plateau), when potential maintained at its equilibrium value, (iv) negative (atp hydrolysis) after all oxygen has been consumed. 3. lag phase, several seconds length, function inhibitor protein content It decreased particles treated remove protein, either prior energisation with NADH, or addition aurovertin, which competes for ATPase. concluded that ATPase inhibits both ATP synthesis hydrolysis 4. release from energised membrane determined production during phase. activation energy this process measured temperature dependence lag, shown be 13.3 kcal/mol, lower than oxidation. 5. dependent on 'energisation' membrane, being presence uncouplers. However, it possible decrease considerably agents collapsed without uncoupling membrane. responded component energisation. 6. A kinetic model energy-dependent dissociation ATPase-inhibitor complex is proposed.