[Comparative properties of mitochondrial and microsomal NAD(P)H-dependent lipid peroxidation].
It was shown that rat liver mitochondria and microsomes contain NADPH- and NADH-dependent systems of enzymatic lipid peroxidation. Activation of the NAD(P)H-dependent process in mitochondria occurs due to inhibition of membrane binding of Fe3+ and Fe2+ by chelators, since the membrane-bound ions of Fe cannot effectively participate in peroxidation. The activity of enzymatic mitochondrial lipid peroxidation decreases at alkaline values of pH. The Michaelis constant for chelated Fe3+ ions under NAD(P)H-dependent mitochondrial peroxidation is by 1,5 order of magnitude more than for microsomal peroxidation. In terms of the chelators' effect on Fe3+ binding by microsomes and peroxidation, as well as pH and Km for Fe3+ the microsomal NADHL-dependent system of lipid peroxidation is similar to mitochondrial NADPH-systems; however, it differs from the latter in the type of dependence of peroxidation on the amount of membranes. Based on the ability of the NADPH-system of microsomes to produce the superoxide radical which participates in initiation of peroxidation together with Fe ions, it is assumed that the decrease of Km for Fe3+ at NAD(P)H-dependent lipid peroxidation in mitochondria and the NADH-process in microsomes can occur in the presence of exogenous sources of active oxygen production.
D000818:Animals; D007425:Intracellular Membranes / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D051381:Rats
D008054:Lipid Peroxides; D009243:NAD; D009249:NADP; D007501:Iron
Sravnitel'naia kharakteristika mitokhondrial'nogo i mikrosomnogo NAD(P) H-zavisimogo pereokisleniia lipidov.