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Improved procedures for N‐terminal sulfonation of peptides for matrix‐assisted laser desorption/ionization post‐source decay peptide sequencing
Author(s) -
Wang Dongxia,
Kalb Suzanne R.,
Cotter Robert J.
Publication year - 2003
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1289
Subject(s) - chemistry , peptide , desorption , matrix assisted laser desorption/ionization , soft laser desorption , ionization , matrix (chemical analysis) , chromatography , terminal (telecommunication) , combinatorial chemistry , analytical chemistry (journal) , organic chemistry , biochemistry , ion , adsorption , telecommunications , computer science
Post source decay (PSD) analysis of precursor ions generated from matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry is a powerful tool for amino acid sequencing and primary structure analysis of proteins. N‐Terminal sulfonation has become an effective derivatization strategy in facilitating de novo peptide sequencing by the formation of predominate y‐type ion series in MALDI PSD spectra. Recently, an effective and inexpensive N‐terminal derivatization method has been reported using 4‐sulfophenyl isothiocyanate (SPITC) as the derivatization reagent (J. Mass. Spectrom. 2003; 38: 373–377). In this paper, we report an improvement in the derivatization procedure with this reagent that involves replacing an organic co‐reagent with other chemicals and eliminating the use of organic solvent. The method is demonstrated on a model peptide and on tryptic digests of two proteins. The results indicate that the improved sulfonation reaction can be implemented with high efficiency under aqueous conditions and that the sensitivity of mass detection can be increased considerably. Copyright © 2003 John Wiley & Sons, Ltd.