title: A novel derivatization method for peptides to increase sensitivity and backbone fragmentation in liquid secondary-ion mass spectra.
abstract: Derivatization is used to increase both negative-ion sensitivity and positive-ion sequence information in the liquid secondary-ion mass spectra (LSIMS) of a series of peptides. The derivatization method involves acylation with pentafluorobenzoyl fluoride in a single-step reaction, and the reaction mixture is applied directly to the probe tip for analysis. Acylation takes place at the unprotected N-terminus, tyrosine, and lysine. The derivatives exhibit increased signal-to-noise ratio for [M-H]- ions, especially where there is not already an acidic amino acid residue in the peptide. In positive-ion LSIMS, the N-terminal group acts to retain the charge at the N-terminus, simplifying the fragmentation by producing N-terminal fragment ions. It also increases positive-ion fragmentation, sometimes very dramatically, making sequence determination more straightforward. The simplicity of the process, together with the enhancements it provides, make this a generally useful method for obtaining peptide structural information.
authors.affiliation: Pfizer Central Research, Groton, CT 06340.
authors.forename: J P
authors.initials: JP
authors.lastname: Kiplinger
authors.forename: L
authors.initials: L
authors.lastname: Contillo
authors.forename: W L
authors.initials: WL
authors.lastname: Hendrick
authors.forename: A
authors.initials: A
authors.lastname: Grodski
mesh_terms: D000595:Amino Acid Sequence; D000805:Angiotensin III / Q000032:analysis; D001920:Bradykinin / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004743:Enkephalin, Leucine / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification*
chemical_list: D007202:Indicators and Reagents; D010455:Peptides; D000805:Angiotensin III; D004743:Enkephalin, Leucine; D001920:Bradykinin