The lipid peroxidation product trarzs-4-hydroxy-2-nonenal(HNE) has been implicated in the covalent modification of low-density lipoproteins (LDL) thought to contribute to the overaccumulation of LDL in the arterial wall in the initial stages of atherosclerosis. Proposals for the exact structures of “early” protein side-chain modifications until now have been based on indirect evidence. In this paper, the structures of first-formed His-and Lys-based ...