Susceptibility of a peptide derived from bradykinin to hydrolysis by brain endo-oligopeptidases and pancreatic proteinases.

The property of brain endopeptidases of attacking small biologically active polypeptides but not denatured proteins led us to compare them with pancreatic proteolytic enzymes with respect to hydrolysis of a synthetic peptide derived from bradykinin (Gly-Gly-Gly-Arg-bradykinin), free, bound to Affi-Gel 10, or bound to succinylated polylysine of 3,000 and 180,000 daltons, respectively. The data show that brain endopeptidases A and B only hydrolyze bradykinin in its free form, whereas trypsin, chymotrypsin, and carboxypeptidase B hydrolyze the polypeptide both free and covalently bound to a high molecular weight carrier. These results suggest that brain endopeptidases selectively hydrolyze low molecular weight polypeptides.