Malondialdehyde modification of proteins in vitro is enhanced in the presence of acetaldehyde

test the hypothesis that the cardioprotective effect of alcohol is related to the inhibition of malondialdehyde (MDA) modification of proteins by acet aldehyde (AA), we studied the effect of AA on MDA modification of bovine se rum albumin (BSA) in vitro. BSA was incubated simultaneously with a fixed c oncentration of MDA (70 mM) and different concentrations of AA (120, 60, 30 , 10, or 0 mM) for 24 h at 37 degreesC. The MDA-modified or AA-modified BSA was quantitated with immunoblotting by using specific anti-MDA and specifi c anti-AA protein antisera, respectively. In another set of experiments, BS A was incubated sequentially, first with different concentrations of AA and then with 70 mM of MDA. In both incubation protocols, the presence of AA a nd AA modification of BSA enhanced MDA binding. These in vitro observations suggest that the putative cardioprotective effects of alcohol or wine cann ot be ascribed to AA-mediated reduction in MDA protein formation, a possibl e biochemical pathway of accelerated atherosclerosis. (C) Elsevier Science Inc. 2001.