THEORETICAL-STUDIES ON CONTROL OF OXIDATIVE-PHOSPHORYLATION IN MUSCLEMITOCHONDRIA AT DIFFERENT ENERGY DEMANDS AND OXYGEN CONCENTRATIONS

The mathematical dynamic model of oxidative phosphorylation in muscle mitochondria developed previously was used to calculate the flux contr ol coefficients of particular steps of this process in isolated mitoch ondria at different amounts of hexokinase and oxygen concentrations. T he pattern of control was completely different under different conditi ons. For normoxic concentration, the main controlling steps in state 4 , state 3.5 and state 3 were proton leak, ATP usage (hexokinase) and c omplex III, respectively. The pattern of control in state 4 was not ch anged at hypoxic oxygen concentration, while in stab 3.5 and state 3 m uch of the cont;ol was shifted from other steps to cytochrome oxidase. The implications of the theoretical results obtained for the regulati on of oxidative phosphorylation in intact muscle are discussed.