A STRUCTURAL ASSIGNMENT FOR A STABLE ACETALDEHYDE-LYSINE ADDUCT

Acetaldehyde is the first oxidation product of ethanol in vivo. Lysine residues in proteins such as hemoglobin have been implicated as targe t structures for acetaldehyde adducts resulting from ethanol consumpti on. Although the presence of both stable and unstable acetaldehyde-hem oglobin adducts has been established, the structural characterization of the adducts has received relatively little attention, As a model fo r such adduct formation, we studied the peptide pentalysine in vitro. Pentalysine has several potential sites for adduct formation, The amin o-terminal amine group as well as the E-amine groups of each lysine si de chain can serve as potential sites for modification by acetaldehyde , Mass spectrometry, nuclear magnetic resonance, and Raman spectroscop y were employed to demonstrate that acetaldehyde forms a stable linkag e to lysine amine groups via a Schiff base.