Pepsin

Crystalline Pepsin

The decrease in protein nitrogen and in the activity of solutions of crystalline pepsin at pH 1.8 and 45 degrees C. has been determined. The decrease in activity, as measured with eleven different methods, is in exact proportion to the decrease of protein nitrogen of the solution. The measurements were continued until less than 5 per cent of the original protein remained. These results indicate...

Crystalline Pepsin Iii. Preparation of Active Crystalline Pepsin from Inactive Denatured Pepsin By

The results (1) of the experiments with crystalline pepsin isolated from crude pepsin preparations indicated that the material is a pure substance and that the proteolytic activity is a property of the protein molecule itself and is not due to the presence of a separate non-protein impurity. No indication of the presence of a more highly active nonprotein molecule was obtained in the solubility...

Transformation of Swine Pepsinogen into Swine Pepsin by Chicken Pepsin

Activation of swine pepsinogen with chicken pepsin results in the formation of swine pepsin. Activation of chicken pepsinogen with swine pepsin results in the formation of chicken pepsin. The structure responsible for the species specificity of the enzyme is therefore present in the inactive precursor.

The Specificity of Pepsin

Pepsinogen and Pepsin

Evidence relating to the structure and properties of swine pepsinogen and pepsin has been reviewed and used to suggest a tentative two dimensional picture of the skeleton of these two proteins. When pepsinogen, a folded single peptide chain, is converted to pepsin, there is a profound change in the physical and chemical properties of the protein. In an as yet unknown manner, except that it is i...