Dangerous byproducts of alcohol breakdown--focus on adducts. Alcohol Res Health 2003; 27: 285-290 2 Brooks PJ. DNA damage, DNA repair, and alcohol toxicity-a review. Alcohol Clin Exp Res 1997; 21: 1073-1082 3 Fraenkel-Conrat H, Singer B. Nucleoside adduct

Alcohol breakdown in the liver results in the generation of the reactive molecule acetaldehyde and, as a byproduct, highly reactive oxygen-containing molecules known as oxygen radicals. Both acetaldehyde and oxygen radicals can interact with proteins and other complex molecules in the cell, forming hybrid compounds called adducts. Other adducts are formed with aldehyde molecules, which are produced through the interaction of oxygen radicals with lipids in the cells. Adduct formation impedes the function of the original proteins participating in the reaction. Moreover, the adducts may induce harmful immune responses. Both of these effects may account for some of the damage observed in alcoholic liver disease. Adduct formation has been shown to occur in the livers of humans and animals consuming alcohol and to start and predominate in those liver regions that show the first signs of liver damage. KEY WORDS: ethanol metabolism; adduct; aldehydes; acetaldehyde; oxygen radicals; alcoholic liver disorder; proteins; immune system; toxic drug effect; lipids; peroxidation; biochemical mechanism Most of the alcohol a person highly reactive oxygen-containing ingests is eliminated from the molecules called oxygen radicals, DEAN J. TUMA, PH.D., is a senior body via a series of chemical including the hydroxyethyl radical research career scientist and director reactions in the liver that are collectively (HER). Excessive production of oxygen of the Omaha VA Alcohol Research referred to as oxidative metabolism. radicals and/or a concurrent deficiency Center, Department of Veterans Affairs