title: Desorption/ionization efficiency of peptides containing disulfide bonds in matrix-assisted laser desorption/ionization mass spectrometry.
abstract: In order to elucidate the role of desorption/ionization efficiency of peptides in MALDI-MS, we focused on peptides with disulfide bonds, which form a rigid tertiary structure.  We synthesized seven sets of peptides with one disulfide bond (oxytocin, somatostatin, [Arg(8)]-vasopressin, [Arg(8)]-vasotocin, cortistatin, melanin-concentrating hormone, urotensin II-related peptide) and five sets of peptides with two disulfide bonds (tertiapin, α-conotoxin GI, α-conotoxin ImI, α-conotoxin MI and α-conotoxin SI).  Each peptide set consisted of three peptides: the oxidized form (S-S type), the reduced form (SH type), and an internal standard peptide in which all cysteine residues were substituted with alanine residues.  In the case of urotensin II-related peptide, tertiapin, α-conotoxin ImI and α-conotoxin MI, the reduced form showed higher desorption/ionization efficiency than the oxidized form.  In contrast, the other peptides revealed higher desorption/ionization efficiency in the oxidized form relative to the reduced form.  These results imply that a rigid structure of peptides formed by disulfide bonds does not correlate with desorption/ionization efficiency in MALDI-MS.
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan. yasushi.shigeri@aist.go.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shigeri
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inazumi
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Hagihara
authors.forename: Akikazu
authors.initials: A
authors.lastname: Yasuda
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakata
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004220:Disulfides; D010446:Peptide Fragments