Tryptophan analysis simultaneously with other amino acids in gas phase hydrochloric acid hydrolyzates using the Pico-TagTM Work Station

Summary Classical liquid phase hydrolysis of proteins with hydrochloric acid in the presence of tryptamine 3-(2-aminoethyl)indole] has shown that tryptophan can be protected from destruction. An exhaustive study has been made to establish the optimum conditions for protein hydrolysis, in the gas phase using the Pico-Tag^TM Work Station, as a function of time and temperature. The amino acid content, including tryptophan and cyst(e)ine, of standard proteins such as lysozyme, human albumin and -chymotrypsin were determined as phenylthiocarbamyl (PTC) derivatives. On 5 m Hypersil columns (15×4.6 mm) the quantitation of twenty PTC amino acids requires 22 minutes. The reproducibility of the measurements was 5.8% (relative standard deviation) or less.