The oxidation of lipids can cause the formation of lipid hydroperoxide followed by the degradation of the peroxide. The formed lipid-decomposition products such as aldehydes can easily react with biomolecules such as proteins (1 ). The aldehyde-derived adduct formation has been examined by many researchers using chemical and immunochemical methods (1 -3 ). However, on the other hand, the lipid hydroperoxide itself might react with protein as already suggested (4 ). We hypothesize that the lipid hydroperoxide-derived modification occurs and specific products derived from the reaction should be formed. In this chapter, we describe the methodology of the preparation of polyclonal antibodies (PAbs) to lipid hydroperoxide-modified proteins. We also show the preparation of the polyclonal antibody to Nε -(hexanoyl)lysine, which is identified as a novel lipid-lysine adduct from the reaction mixture of linoleic acid hydroperoxide and lysine (5 ).
