Amino acid sequence determination by gas chromatography—mass spectrometry of permethylated peptides : The application of capillary columns

Abstract

The application of capillary columns to the determination of the amino acid sequence of proteins and polypeptides by gas chromatography—mass spectrometry (GC—MS) of partial hydrolysates is described and discussed for the case of the Nα,ε-trifluoroacetyl-N,O-permethyl derivatives. Retention indices are determined with the aid of a computer program. The mass spectra of methionine enkephalin obtained by GC—MS on a packed and on a capillary column are presented and a retention index calculated. Amounts of derivative corresponding to sub-nanomole amounts of peptides are sufficient to provide full amino acid sequence information. To assist in the assignment of retention indices above 4400, a mixture of n-alkanes from a commercial source was characterized by GC—MS up to n-C54H110, and was found to contain material up to an expected C72H146.