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Identification of the nitration site of insulin by peroxynitrite
Author(s) -
Chi Quan,
Huang Kaixun
Publication year - 2007
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.805
Subject(s) - peroxynitrite , nitration , chemistry , insulin , tyrosine , biochemistry , peroxynitrous acid , peptide , enzyme , organic chemistry , endocrinology , superoxide , biology
Our previous investigation indicated that insulin can be nitrated by peroxynitrite in vitro . In this study, the preferential nitration site of the four tyrosine residues in insulin molecule was confirmed. Mononitrated and dinitrated insulins were purified by RP‐HPLC. Following reduction of insulin disulfide bridges, Native‐PAGE indicated that A‐chain was preferentially nitrated. Combination of enzymatic digestion of mononitrated insulin with endoproteinase Glu‐C, mass spectrometry confirmed that Tyr‐A14 was the preferential nitration site when insulin was treated with peroxynitrite. Tyr‐A19, maybe, was the next preferential nitration site. According to the crystal structure, Tyr‐B26 between the two tyrosine residues in insulin B‐chain was likely easier to be nitrated by peroxynitrite. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.