title: Enrichment and identification of cysteine-containing peptides from tryptic digests of performic oxidized proteins by strong cation exchange LC and MALDI-TOF/TOF MS.
abstract: The extreme complexity of sample and uninformative fragmentation of peptides in MS/MS experiments are two of several real challenges faced by proteomics. In this work, a strategy aimed at tackling these two problems is presented. Briefly, proteins were first oxidized by performic acid to cleave the disulfide bonds and simultaneously convert cysteine residue into its sulfonic form. Then the resultant sulfonic peptides were enriched by SCX chromatography, exploiting the negative solution charge of sulfonic group. The sulfonic peptide could be easily detected by MALDI-MS in negative mode and showed both enhanced fragmentation efficiency and a simplified spectrum in MALDI-MS/MS experiment in positive mode. The strength of the strategy was demonstrated by applying it to bovine serum albumin. Potential use of the strategy in proteomics was also discussed.
authors.affiliation: Beijing Institute of Radiation Medicine, China.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Dai
authors.forename: Jinglan
authors.initials: J
authors.lastname: Wang
authors.forename: Yangjun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Lu
authors.forename: Bing
authors.initials: B
authors.lastname: Yang
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Li
authors.forename: Yun
authors.initials: Y
authors.lastname: Cai
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Qian
mesh_terms: D000595:Amino Acid Sequence; D002411:Cation Exchange Resins / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002852:Chromatography, Ion Exchange / Q000379:methods*; D003545:Cysteine / Q000032:analysis* / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D002411:Cation Exchange Resins; D002412:Cations; D010446:Peptide Fragments; D011506:Proteins; D003545:Cysteine