N-nitrosations of basic amino acid residues in polypeptide.

Changes in the electrophoretic pattern were noted in the products of polypeptides of identical basic amino acids preincubated with reactive or degraded PN, suggesting the occurrence of N-nitrosation of the epsilon-amino group of lysine, the guanido group of arginine and the imidazole group of histidine. Additionally, increase in the N-nitroso immunoreactivity of preincubated histones H2A and H2B was detected by Western blot analysis.

N-nitrosation and denitrosation on lysine residues of histones.

Increased immunoactivity of (-nitrosolysine was detected in Western blot in peroxynitrite-reacted histones H2A, H3 and H4. The N-nitrosation may be reversible as indicated by the decreased immunoactivity via either subsequent incubation with reduced glutathione or 48-hour dialysis and 48-hour storage at 4 degrees C. Nonetheless, the biological significance of N-nitrosation of protein lysine is yet to be proven.