Inhibition of Ca(2+)-induced aggregation of porcine intestinal brush-border membranes by lipid peroxidation.
The effects of lipid peroxidation on Ca(2+)-induced aggregation of porcine intestinal brush-border membranes were examined using a system consisting of ascorbic acid/Fe2+/tert-butyl hydroperoxide (t-BuOOH). Incubation of the membranes with ascorbic acid/Fe2+/t-BuOOH resulted in inhibition of Ca(2+)-induced aggregation of the membranes with the formation of thiobarbituric acid-reactive substances, depending on the hydroperoxide concentration and the incubation time. The inhibition of the membrane aggregation associated with ascorbic acid/Fe2+/t-BuOOH treatment was effectively prevented by the addition of an antioxidant, 3(2)-tert-butyl-4-hydroxyanisole, to the reaction mixture. Studies with 8-anilino-1-naphthalenesulfonate (ANS) revealed that there is a linear relationship between the apparent dissociation constants (Kd) of ANS-membrane complexes and the aggregating efficiencies of the membranes with different levels of lipid peroxidation This suggests that inhibition of the membrane aggregation by lipid peroxidation involves a change in the membrane surface charge density. Modification of the membranes with malondialdehyde also resulted in a decrease in the aggregating efficiency of the membranes with a decrease in the Kd value of ANS-membrane complex. In addition, the contribution of the lipid organization to membrane aggregation was examined by measuring the fluorescence anisotropy of diphenylhexatriene-labeled membranes in the presence of a lipid fluidizer, benzyl alcohol. The results are discussed in terms of peroxidation-induced inhibition of intramembrane interactions of the membranes.
Ohyashiki
T
T
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Ishikawa.
Takino
T
T
Matsui
K
K
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology / Q000648:ultrastructure*; D007501:Iron / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000502:physiology*; D008055:Lipids / Q000502:physiology; D008315:Malondialdehyde / Q000494:pharmacology; D008560:Membrane Fluidity / Q000187:drug effects; D008564:Membrane Potentials / Q000502:physiology; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D009391:Nephelometry and Turbidimetry; D016877:Oxidants / Q000494:pharmacology; D010545:Peroxides / Q000494:pharmacology; D013552:Swine; D013997:Time Factors; D020122:tert-Butylhydroperoxide
D008055:Lipids; D016877:Oxidants; D010545:Peroxides; D008315:Malondialdehyde; D020122:tert-Butylhydroperoxide; D007501:Iron; D001205:Ascorbic Acid; D002118:Calcium