SOME CHARACTERISTICS OF THE NAD(P)H-DEPENDENT LIPID PEROXIDATION SYSTEM IN THE MICROSOMAL FRACTION OF CHICKEN BREAST MUSCLE

Incubation of the microsomal fraction isolated from chicken breast muscle in the presence of NADPH, ADP and Fe⁺⁺⁺ ions was shown to result in lipid peroxidation. NADH was able to replace NADPH as the source of reducing equivalents but was less efficient. The pH optimum for malonaldehyde (MDA) production was found to be around pH 6. 7. Oxygen uptake by the system was shown to have a pH optimum of 5.5. Oxygen uptake was approximately linearly dependent on temperature but malonaldehyde production exhibited a sharp increase between 25°C and 37°C. Inhibitor studies and the virtual absence of cytochromes indicate that this system is not similar to that isolated from rat liver microsomes. The activity of the lipid peroxidation system was maintained after storage for 7 days at pH 7.25 and 4°C. At pH 5.6 a reduction in activity was noted after 7 days.