The activation of chymotrypsinogen isolation and identification of a peptide liberated during activation

Abstract

Reactions attending the conversion of precursors of proteolytic enzymes to the active form are distinguished by several features of unusual interest: (a) they are enzyme-catalyzed; (b) they are irreversible; (c) they involve the opening of a limited number of peptide bonds; (d) they provide an experimental system for the study of the final steps in formation of a biologically specific protein and of the relation of chemical structure to biological activity of proteins. In recent studies in this laboratory, including the present work, several intermediates formed during the activation of chymotrypsinogen have been recognized by a combination of methods. These have included electrophoresis, end-group analysis, enzymatic activity, peptide analysis, and sedimentation. As a result of the present experimental study, which dealt in particular with the nature of the peptide released during the rapid activation of chymotrypsinogen, it has been possible to identify the nature of the limited number of peptide bonds hydrolyzed during the activation process.