TY - JOUR
T1 - Relative quantitation of protein nitration by liquid chromatography-mass spectrometry using isotope-coded dimethyl labeling and chemoprecipitation
AU - Guo, Jia
AU - Prokai-Tatrai, Katalin
AU - Prokai, Laszlo
N1 - Funding Information:
This work was supported in part by the National Institutes of Health (grant number AG025384 ) and the Robert A. Welch Foundation (endowment BK-0031 ).
PY - 2012/4/6
Y1 - 2012/4/6
N2 - Protein nitration has been recognized as an important biomarker for nitroxidative stress associated with various diseases. While identification of protein targets for nitration is important, its quantitative profiling also is necessary to understand the biological impact of this low-abundance posttranslational modification. We have previously reported an efficient and straightforward enrichment method for nitropeptides to reduce sample complexity and permit unambiguous site-specific identifications by LC-MS analyses. This approach relies on two chemical derivatization steps: specifically reductive methylation of aliphatic amines and, then, conversion of nitrotyrosines to the corresponding aminotyrosines before their selective capture by a solid-phase reagent we introduced previously. Hence, the method inherently offers the opportunity for relative quantitation of nitropeptides by using isotopic variants of formaldehyde for reductive methylation. This simple method was tested via LC-MS analyses of differently N-methylated nitropeptides and nitroubiquitin as a model nitroprotein enriched from human serum albumin digest and from human plasma, respectively.
AB - Protein nitration has been recognized as an important biomarker for nitroxidative stress associated with various diseases. While identification of protein targets for nitration is important, its quantitative profiling also is necessary to understand the biological impact of this low-abundance posttranslational modification. We have previously reported an efficient and straightforward enrichment method for nitropeptides to reduce sample complexity and permit unambiguous site-specific identifications by LC-MS analyses. This approach relies on two chemical derivatization steps: specifically reductive methylation of aliphatic amines and, then, conversion of nitrotyrosines to the corresponding aminotyrosines before their selective capture by a solid-phase reagent we introduced previously. Hence, the method inherently offers the opportunity for relative quantitation of nitropeptides by using isotopic variants of formaldehyde for reductive methylation. This simple method was tested via LC-MS analyses of differently N-methylated nitropeptides and nitroubiquitin as a model nitroprotein enriched from human serum albumin digest and from human plasma, respectively.
KW - Enrichment
KW - LC-MS
KW - Protein nitration
KW - Relative quantitation
KW - Stable-isotope labeling
KW - Tandem mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=84858076159&partnerID=8YFLogxK
U2 - 10.1016/j.chroma.2011.12.100
DO - 10.1016/j.chroma.2011.12.100
M3 - Article
C2 - 22285050
AN - SCOPUS:84858076159
VL - 1232
SP - 266
EP - 275
JO - Journal of Chromatography A
JF - Journal of Chromatography A
SN - 0021-9673
ER -