The inhibitory effect of lipid peroxide on the activity of the membrane-bound and the solubilized lipoprotein lipase.
The effects of lipid peroxide (15-hydroperoxy arachidonic acid) on the activity of lipoprotein lipase was investigated. The activities were examined in 2 enzyme species: the lipoprotein lipase bound to the coronary vessels of the rat heart and that solubilized in the human post-heparin plasma. As a substrate, 3H-labelled human chylomicron was used. Lipid peroxide decreased the maximal velocity of the reaction between the chylomicron and lipoprotein lipase on the vascular surface. In the post-heparin plasma, the lipid peroxide decreased the maximal hydrolysis rate, but did not change the half life time in the unsaturated reaction. It is suggested that lipid peroxide directly damages a part of the membrane-bound lipoprotein lipase, and that the degeneration of cell membranes and the vasoconstriction caused by lipid peroxide will additionally disturb the hydrolysis of the plasma triglyceride on the vascular surface.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003331:Coronary Vessels / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D066298:In Vitro Techniques; D008054:Lipid Peroxides / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051381:Rats; D012995:Solubility
D008054:Lipid Peroxides; D008071:Lipoprotein Lipase