Sequence determination by partial methanolysis and fast atom bombardment (FAB) mass spectrometry of peptides containing cysteine and methionine was investigated. Cysteine-containing peptides require methylation of the sulphydryl group by methyl iodide to give a stable S-methylcysteinyl residue prior to partial methanolysis and mass spectrometry. Methionine-containing peptides undergo partially a methylation on sulphur during methanolysis, with formation of an S-methylsulphonium ion which under FAB conditions is extracted from the matrix and eliminates methyl sulphide in the gas phase. The presence of additional peaks due to chemical modifications or gas-phase fragmentations, however, does not interfere with the sequence information of the spectra.

PARTIAL METHANOLYSIS AND FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY OF PEPTIDES CONTAINING SULFURATED AMINO-ACIDS

FOTI, Salvatore;SALETTI, Rosaria;MARLETTA, DONATA
1991-01-01

Abstract

Sequence determination by partial methanolysis and fast atom bombardment (FAB) mass spectrometry of peptides containing cysteine and methionine was investigated. Cysteine-containing peptides require methylation of the sulphydryl group by methyl iodide to give a stable S-methylcysteinyl residue prior to partial methanolysis and mass spectrometry. Methionine-containing peptides undergo partially a methylation on sulphur during methanolysis, with formation of an S-methylsulphonium ion which under FAB conditions is extracted from the matrix and eliminates methyl sulphide in the gas phase. The presence of additional peaks due to chemical modifications or gas-phase fragmentations, however, does not interfere with the sequence information of the spectra.
1991
SEQUENCE DETERMINATION; HYDROLYSIS,; ANALOGS
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/62768
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