Isolation of tryptophan-containing peptides by adsorption chromatography

A general method for the isolation of modified tryptophan-containing peptides is described, which takes advantage of the adsorption properties of tale for aromatic nitrocompounds. The method has been extensively assayed on tryptic and chymotryptic hydrolyzates of human Bence Jones proteins of k and λ type and of human serum albumin, and in preliminary experiments on egg white lysozyme and rabbit IgG light chains. All those proteins had been previously carboxymethylated and modified with 2,4 dinitrophenylsulfenylchloride, a selective reagent for tryptophan.