title: Direct MALDI-MS analysis of the disulfide bonds in peptide using thiosalicylic acid as a reactive matrix.
abstract: The ability of a thiol-containing molecule, thiosalicylic acid (TSA), to function as a reactive matrix for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry analysis of peptides has been investigated. Although TSA has reducing characteristics, the use of TSA did not cause a reduction-induced MALDI in-source decay, probably because of the weak interactions between the thiol group in TSA and the carboxyl oxygen in the peptide. In contrast, when peptides containing disulfide bonds were analyzed by MALDI with TSA as the matrix, the disulfide bond was partially cleaved owing to the reaction with TSA, producing TSA-adducted peptides. The reaction between the disulfide bond and TSA was suggested to be occurred in solution. The comparison of the MALDI mass spectra obtained using conventional matrix and TSA allows us to count the number of disulfide bonds in the peptides. Copyright © 2017 John Wiley & Sons, Ltd.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
authors.forename: D
authors.identifier: 0000-0002-9357-8420
authors.initials: D
authors.lastname: Asakawa
authors.affiliation: Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1211, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Osaka
mesh_terms: D000595:Amino Acid Sequence; D020916:Conotoxins / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D012459:Salicylates / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013373:Substance P / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014667:Vasopressins / Q000737:chemistry
chemical_list: D020916:Conotoxins; D004220:Disulfides; D010455:Peptides; D012459:Salicylates; D012709:Serum Albumin; D013438:Sulfhydryl Compounds; D014667:Vasopressins; D013373:Substance P; C441201:thiosalicylic acid
keywords: MALDI matrix; hydrogen atom donor; in-source decay; number of disulfide bonds; thiol