ALDEHYDE-INDUCED PROTEIN MODIFICATIONS IN HUMAN PLASMA - PROTECTION BY GLUTATHIONE AND DIHYDROLIPOIC ACID

Exposure of human plasma to gas phase cigarette smoke (CS) produces a depletion of ascorbic acid, peroxidation of lipids (Frei et al. Bioche m J 1991;277:133-8), and protein modification (as measured by protein carbonyl accumulation and loss of sulfhydryl groups) (Reznick et al.Bi ochem J 1992;286:607-11). CS contains both saturated and unsaturated a ldehydes. The contribution of these aldehydes to the damaging effects of CS on human plasma was investigated. Aldehydes present in CS did no t cause a depletion of plasma antioxidants such as ascorbic acid or al pha-tocopherol and did not induce plasma lipid peroxidation. Aldehydes decreased plasma protein sulfhydryl concentrations but increased prot ein carbonyls. The thiols glutathione and dihydrolipoic acid had a sig nificant effect in reducing aldehyde-induced protein modifications.