21—A PRELIMINARY INVESTIGATION OF THE PRODUCTS OF PARTIAL ACID HYDROLYSIS OF γ-KERATOSE

The rate of hydrolysis of y-keratose in 5N HCl at 37°C has been followed by determination of the free amino groups formed. A partial hydrolysate of γ-keratose has been prepared in which the average chain length of the peptides was two amino-acid residues. This partial hydrolysate has been fractionated, first by ion-exchange chromatography and then by two-dimensional paper chroniatography or high-voltage paper electrophoresis. Fifteen di- and tripeptides have been identified, and several other peptides containing up to five amino-acid residues were found to be possibly present in the hydrolysate. In particular, cysteylcysteic acid has been shown to be present in γ-keratose, although previous workers have denied its presence.