title: Fragmentation of protonated ions of peptides containing cysteine, cysteine sulfinic acid, and cysteine sulfonic acid.
abstract: The oxidation of the sulfhydryl group in cysteine to sulfenic acid, sulfinic acid, and sulfonic acid in proteins is important in a number of enzymatic processes. In this study we examined the fragmentation of four peptides containing cysteine, cysteine sulfinic acid (Cys-SO(2)H), and cysteine sulfonic acid (Cys-SO(3)H) in an ion-trap mass spectrometer. Our results show that the presence of a Cys-SO(2)H in a peptide leads to preferential cleavage of the amide bond at the C-terminal side of the oxidized cysteine residue. The results are important for the determination of the site of the cysteine oxidation and might be useful for the sequencing of cysteine-containing peptides.
authors.affiliation: Department of Chemistry, University of California at Riveirside, Riverside, California 92521-0403, USA. yinsheng.wang@ucr.edu
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Shetty
authors.initials: S
authors.lastname: Vivekananda
authors.forename: Lijie
authors.initials: L
authors.lastname: Men
authors.forename: Qibin
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D018377:Neurotransmitter Agents; D010455:Peptides / Q000737:chemistry*; D011522:Protons; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D007477:Ions; D018377:Neurotransmitter Agents; D010455:Peptides; D011522:Protons; D013451:Sulfonic Acids; D003545:Cysteine; C013461:cysteine sulfinic acid