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.
|Titolo:||PARTIAL METHANOLYSIS AND FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY OF PEPTIDES CONTAINING SULFURATED AMINO-ACIDS|
|Data di pubblicazione:||1991|
|Appare nelle tipologie:||1.1 Articolo in rivista|