Preferential cleavage at aspartyl-prolyl peptide bonds in dilute acid.

A simple, rapid technique is presented for preferential cleavage at aspartylprolyl peptide bonds. The method is based upon the fact that these peptide bonds are 8-20-fold more labile in 0.015 N HCl at 100-110 degrees than other aspartyl-X or X-aspartyl peptide bonds. The method has proven effective in the cleavage of several peptides from pig kidney fructose-1,6-bisphosphatase and should facilitate sequence analysis of proteins that contain aspartyl-prolyl linkages.