title: Partial reduction and two-step modification of proteins for identification of disulfide bonds.
abstract: An experimental protocol was established to combine partial reduction, cyanylation, and a second modification step for the assignment of disulfide bonds in proteins that are resistant to proteolysis under native conditions. After proteolysis, disulfide bonds were assigned via MALDI mass spectrometry with subsequent semiautomatic interpretation using the program SearchXLinks, which enumerates all possible combinations of proteolytic fragments for all observed monoisotopic masses. The putative assignment of disulfide bonds was confirmed by ISD and PSD fragmentation of the corresponding protonated molecules.
authors.affiliation: Center of Advanced European Studies and Research, Stiftung caesar, Bonn, Germany. schnaible@caesar.de
authors.forename: Volker
authors.initials: V
authors.lastname: Schnaible
authors.forename: Stephan
authors.initials: S
authors.lastname: Wefing
authors.forename: Anne
authors.initials: A
authors.lastname: Bücker
authors.forename: Sybille
authors.initials: S
authors.lastname: Wolf-Kümmeth
authors.forename: Daniel
authors.initials: D
authors.lastname: Hoffmann
mesh_terms: D000465:Algorithms; D000818:Animals; D002417:Cattle; D004220:Disulfides / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry; D010447:Peptide Hydrolases / Q000378:metabolism; D011506:Proteins / Q000032:analysis / Q000737:chemistry*; D012259:Ribonuclease, Pancreatic / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004220:Disulfides; D010446:Peptide Fragments; D011506:Proteins; D012259:Ribonuclease, Pancreatic; D010447:Peptide Hydrolases