Anionic Trypsinogen Research Articles

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.

Digestive proteases in the holocephalian fish Chimaera monstrosa (L.)

1. 1. In a pancreatic extract from Chimaera montrosa, activated with bovine trypsin, or an extract from the intestinal mucosa (“enterokinase”), the proteolytic enzymes trypsin, chymotrypsin, elastase and carboxypeptidase A and B were found. 2. 2. In an extract from the intestinal mucosa dipeptidase and leucineaminopepditase activities were observed. They probably act intracellularly because these enzymes were not found in the intestinal juice. 3. 3. For the tryptic and chymotryptic activities pH optima and Michaelis-Menten constants were recorded. 4. 4. The tryptic activity was inhibited by soy bean trypsin inhibitor, DFP and TLCK. The chymotryptic activity was inhibited by DFP and TPCK. 5. 5. With agar electrophoresis of extracts from the pancreas and intestinal mucosa anionic trypsinogen and trypsin, cationic chymotrypsinogen and chymotrypsin, as well as “enterokinase”, were separated. 6. 6. The gastrointestinal hormones secretin and pancreozymin have been extracted from the intestinal mucosa.

On chymotrypsinogen and trypsinogen biosynthesis by pancreas of rats fed on a starch-rich or a casein-rich diet

Tissue and mRNA levels of trypsin and the two forms of pancreatic secretory trypsin inhibitor (PSTI) were determined in the pancreatic tissue of rats fed on either a protein-free diet or two high-protein diets (44% and 64% protein, respectively) for 10 days as compared with control rats fed on a standard diet (22% protein). Two distinct response patterns were obtained, depending on the animals' nutritional status after ingestion of the protein-free and high-protein diets. After administration of the protein-free diet (containing 81% carbohydrate), the levels of the two mRNAs encoding both forms of the secretory trypsin inhibitor and anionic trypsinogen I increased significantly (100%, 110%, and 110%, respectively), whereas no significant increase in both PSTI mRNA levels were observed after the ingestion of the high-protein diets as compared with the control rats. Under all three dietary conditions, a coordinated pattern of response was observed between the two forms of inhibitors and anionic trypsinogen I at both the tissue mRNA and protein levels. The existence of a parallel change in trypsin activity and secretory trypsin inhibitor activity on the one hand, and trypsin mRNA and inhibitor mRNAs on the other hand, suggests that indentical influences regulate the expression of trypsin and pancreatic secretory trypsin inhibitor genes in response to the dietary protein content.