l-tty(troxy 2-nonenal (ttNE), a major product of lipid peroxidation, readily reacts with cysteine, histidine, and lysine residues on protein. Incubation of protein with tlNE results in enzyme inactivation, protein cross-linking and the formation of fluorescent material reminiscent of lipofuscin and ceroid pigments, intracellular aggregates of damaged protein which accumulate as a function of age and disease. It is therefore critical to characterize the chemistry by which lINE reacts with protein in order to assess the relevance of such reactions 1o pathophysiological conditions associated with oxidative stress. We have observed the formation of a fluorescent compound from the reaction of tINF with N-acetyllysine. The IV-\'IS and fluorescent properties of this compound are identical to those observed when protein is incubated with ItNE. FAB-MS of this fluorophoro revealed a Nit/+ of 511 indicating a molecule derived from two molecules of N-acetyllysine and one molecule of HNE with the loss of four hydrogen atoms. Fhe detailed structure of this fluorophore is presently under investigation using l tt and t3C NMR analyses. Polyclonal antibodies specific to the lysine-ltNE fluorophore were prepared. The antibodies were used to detect this modification in biological samples exposed to oxidative stress and to assess age-related differences in the level of its formation in vivo. The results of this study indicate a mechanism for the build-up of altered forms of protein (luring aging and the progression of certain diseases.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology