title: Electrospray ionization mass spectroscopic analysis of peptides modified with N-ethylmaleimide or iodoacetanilide.
abstract: The cysteine-specific modifiers we reported previously, N-ethylmaleimide (NEM) and iodoacetanilide (IAA), have been applied to label cysteine residues of peptides in combination with electrospray ionization mass spectrometry (ESI-MS/MS), and their scope in proteomic studies was examined. Peptides modified with N-ethylmaleimide (NEM) or iodoacetanilide (IAA) showed significant enhancement in ionization efficiencies. These modifiers were also found to remain intact in tandem mass spectrometry. Both combinations of N-ethylmaleimide (NEM) and d(5)-N-ethylmaleimide (d(5)-NEM), and iodoacetanilide (IAA) and (13)C(6)-iodoacetanilide ((13)C(6)-IAA) were also shown to be applicable to quantitative analysis of a peptide.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University, PO Box 41061, Lubbock, TX 79409-1061, USA.
authors.forename: Masoud
authors.initials: M
authors.lastname: Zabet-Moghaddam
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kawamura
authors.forename: Emi
authors.initials: E
authors.lastname: Yatagai
authors.forename: Satomi
authors.initials: S
authors.lastname: Niwayama
mesh_terms: D000083:Acetanilides / Q000737:chemistry*; D000595:Amino Acid Sequence; D005033:Ethylmaleimide / Q000737:chemistry*; D006847:Hydrocarbons, Iodinated / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D040901:Proteomics; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D000083:Acetanilides; D006847:Hydrocarbons, Iodinated; D010455:Peptides; D005033:Ethylmaleimide