Critical kinetic parameters and rate constants representing lipid peroxidation as affected by temperature

Abstract

This study aimed to comparatively investigate the temperature effect on the kinetic parameters and rate constants representing lipid hydroperoxides (LOOH) formation and decomposition during initiation and propagation peroxidations. The initiation phase was characterized by induction period IP, overall initiation rate constant kIP, initiation oxidizability Oi, and the critical reverse micelle concentration of LOOH, CMCL. The propagation phase was characterized by its duration tp, the maximum rate of LOOH accumulation Rmax, maximum LOOH concentration [LOOH]max, propagation oxidizability Rn, composite rate constant kc, and LOOH decomposition rate constant kd. Oi and Rn indicated relatively high dependencies on temperature, respectively. Among the rate constants, kd better highlighted oxidizabilities as affected by temperature. The oxidizabilities had good correspondences with the Arrhenius kinetic (A and Ea) and Eyring thermodynamic (ΔS++ and ΔH++) parameters. The most endergonic reactions (ΔG++>0) were LOOH decompositions, followed by LOOH formations during the propagation and initiation phases, respectively.