title: Kallikrein isolated from commercial crystalline pepsin preparations.
abstract: 1. An experiment designed to study the relationship between pH and kininogenase activity of three commercial preparations of porcine crystallized pepsin showed that each preparation had two well separated pH optima, pH 4 and 8. 2. From the inhibition spectrum of the pH 8 kininogenase it was concluded that it is a kallikrein of the glandular type, since it proved to be a serine protease and was insensitive to protein trypsin inhibitors. 3. Kallikrein activity can be separated from pepsin by affinity chromatography on Sepharose-4B-Pro-Phe-agmatine. This separation permitted us to obtain purified material with kallikrein specific activity 43 times higher than that of crude pepsin and which showed a single band on polyacrylamide gel electrophoresis. 4. The kallikrein activity was found to have a molecular weight of 36 kDal and a Michaelis constant of 25 microM when acting on Bz-Pro-Phe-Arg-p-nitroanilide at pH 8.6. 5. On the basis of these properties, kallikrein from commercial pepsin resembles the kallikreins previously described from rat or human stomach.
mesh_terms: D000818:Animals; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007610:Kallikreins / Q000097:blood / Q000302:isolation & purification* / Q000378:metabolism / Q000652:urine; D010434:Pepsin A / Q000032:analysis* / Q000378:metabolism; D012463:Saliva / Q000201:enzymology; D013552:Swine
chemical_list: D007610:Kallikreins; D010434:Pepsin A