Table II.

Summary of misidentified nitrotyrosine peptides from Hong et al. (21) as verified by de novo sequencing and ESI-MS/MS analysis of synthetic peptides

Reported nitrated peptide sequencea	Charge state	Actual peptide sequence	Charge state	Theoretical m/z difference	Approximate theoretical resolution (M/ΔM) required to resolve ESI-generated ions of reported nitrated peptide from those of actual peptide
EY*RKDLEESIR	2	KVQHELDEAEER	2	0.00	N/Ab
ERYAAWoxMIY*TY*SGLFCVTVNPYK	3	DQEGQDVLLFIDNIFR	2	−0.38	2,500
Y*EEEIK	1	SIHELEK	1	−0.084	10,000
SYKY*LLLSMVK	2	NLVHIITHGEEK	2	−0.0019	350,000

^aoxM, oxidized methionine; *, nitration.

^bNot applicable.