benzyloxycarbonyl-isoleucyl-glutamyl(o-tert-butyl)-alanyl-leucinal and 3-nitrotyrosine

3-Nitrotyrosine (3-NT) is a specific marker of protein nitration by peroxynitrite (ONOO-) produced from nitric oxide and superoxide. Increase in 3-NT containing protein (3-NT protein) was reported in brains from patients with some neurodegenerative disorders and aging. In this paper, intracellular localization of 3-NT protein was examined in dopaminergic SH-SY5Y cells using the selective antibody against protein-bound 3-NT. 3-NT protein was detected in plasma membrane/nucleus and mitochondria fractions, and interestingly in polypeptide composition of mitochondrial complex I. ONOO--generating SIN-1 induced apoptotic cell death with concomitant increase in 3-NT protein and reduction in mitochondrial ATP synthesis. In addition, an inhibitor of proteasomes, carbobenzoxy-L-isoleucyl-gamma-t-butyl-L-glutamyl-L-alanyl-L-leucinal, enhanced the effects of ONOO-. These results suggest that ONOO- may induce mitochondrial dysfunction and cell death in neurons through nitration of mitochondrial complex I subunits.

Topics: Adenosine Triphosphate; Apoptosis; Cell Death; Cysteine Proteinase Inhibitors; Dopamine; Electron Transport Complex I; Humans; Mitochondria; Molsidomine; NADH, NADPH Oxidoreductases; Nitric Oxide Donors; Oligopeptides; Peroxynitrous Acid; Subcellular Fractions; Tumor Cells, Cultured; Tyrosine