The activation of pepsinogen.

Abstract

The activation of purified pepsinogen was studied at pH 2.0 and 5.6 and at 20°C and 0°C. It was found to be catalyzed by hydrogen ions at pH 2.0 and to be truly autocatalytic only at pH 5.6 and 0°C. A certain number of peptides produced during activation were isolated, the rate of formation of the main peptide was found to be identical with the rate of formation of pepsin. The production of the other important peptides could be explained only by assuming that more than one species of active pepsin is produced during activation. It is concluded that the production of each species of active pepsin involves the cleavage of only one peptide bond in each case.