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.