A rapid, sensitive mass spectrometric method for investigating microscale chemical reactions of surface adsorbed peptides and proteins.

A new mass spectrometric method for measuring the products of reactions of surface adsorbed peptides and proteins is described. The technique is rapid, convenient, and sensitive and provides detailed information concerning the molecular weights of the reaction products and the rate and extent of reaction. The properties of the technique are illustrated by an investigation of cleavage reactions of the disulfide bonds in bovine insulin, cyclic somatostatin, and conotoxin G1 utilizing the reducing agent dithiothreitol.