Inactivation of pepsin by diphenyldiazomethane.

Abstract
Diphenyldiazomethane (DDM) rapidly inactivates crystalline swine pepsin at pH 5, as measured by its enzymic activity toward hemoglobin and acetyl-L-phenylalanyl-L-tyrosine. With C14-labeled DDM, radioactivity is incorporated into the protein, presumably by esterifica-tion of reactive carboxyl groups. Treatment of pepsinogen with labeled DDM causes an inhibition of its potential enzymic activity, with incorporation of C14 into the protein.