Studies of an Anionic Trypsinogen and Its Active Enzyme from Porcine Pancreas

Abstract An anionic trypsinogen has been identified and isolated in a state of high purity from porcine pancreatic tissue and juice extracts. The anionic trypsinogen is present in large amounts and accounts for about half of the total potential tryptic activity. The kinetics of the conversion of the anionic trypsinogen to active enzyme is autocatalytic, yielding an anionic trypsin which is less anionic than the zymogen. Km values and specific activities of anionic trypsin toward esters and anilides of arginine and lysine were found to be very similar to those of cationic trypsin. Soybean trypsin inhibitor and diisopropyl phosphorofluoridate are potent inhibitors of anionic trypsin.