Fragmentation of protonated ions of peptides containing cysteine, cysteine sulfinic acid, and cysteine sulfonic acid.
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.
Wang
Yinsheng
Y
Department of Chemistry, University of California at Riveirside, Riverside, California 92521-0403, USA. yinsheng.wang@ucr.edu
Vivekananda
Shetty
S
Men
Lijie
L
Zhang
Qibin
Q
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*
D007477:Ions; D018377:Neurotransmitter Agents; D010455:Peptides; D011522:Protons; D013451:Sulfonic Acids; D003545:Cysteine; C013461:cysteine sulfinic acid