Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein digestion is a complex process in which most aspects have a developmental pattern of activity. Gastric pH and intestinal peptide and amino acid transport as well as the activities of pepsinogen, trypsin, chymotrypsin, enterokinase and intestinal dipeptidases vary during development. No one species has been assessed for all these aspects and it is not possible to present an integrated developmental view of protein digestion. The following developmental changes, however, have been observed. Gastric pH declines, and peptic and pancreatic proteases exhibit increasing activity in pigs and rats after birth. The increase in pigs is gradual over several weeks starting at birth, whereas the increases in the rat begin at 2 wk, just prior to the time of weaning. The activities of dipeptidases in the rat and pig, peptide transport systems in the guinea pig and rabbit and amino acid transport systems in the rat, rabbit, guinea pig and chicken, however, appear (with few exceptions) to be active in the small intestine at the time of birth. Frequently, these activities peak in the neonate and decline during the postnatal period. In the rat, dietary protein tends to increase the activities of pancreatic proteases and intestinal peptidases and to increase the rate of uptake of amino acids by the intestinal epithelium. Individual dietary amino acids also influence amino acid transport systems. The data indicate that most processes in protein digestion undergo marked changes during prenatal and postnatal development and are influenced by the level of feeding and composition of the diet.
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PMID:Development and adaptation of protein digestion. 388 40

The cascade enterokinase-trypsinogen-prophospholipase A2 lecithin, generating trypsin, phospholipase A2 and lysolecithin, respectively, was studied in vitro using a novel phospholipase A2 assay. The rate of enterokinase catalysed activation of trypsinogen was maximal at 4 mmol/1 glycodeoxycholic acid; higher concentrations of bile salt progressively inhibited enterokinase activity. Net phospholipase A2 activity in reaction mixtures was critically dependent on the trypsin/prophospholipase A2 molar ratio. Lecithin hydrolysis by phospholipase A2 was dependent on the bile salt/lecithin molar ratio and was optimal at 1.25 to 1. The addition of enterokinase to lecithin and bile salt mixtures, containing trypsinogen and prophospholipase A2 at presumed pathophysiological concentrations, resulted in the generation of concentrations of lysolecithin lytic for pancreatic acinar cells within 5 min. These findings would support the concept that the entry of bile containing active enterokinase into the pancreatic duct system in vivo may in some cases be involved in the initiation of necrotising acute pancreatitis in man.
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PMID:The generation of lysolecithin by enterokinase in trypsinogen prophospholipase A2 lecithin mixtures, and its relevance to the pathogenesis of acute necrotising pancreatitis. 390 74

Chronic diversion of pancreatic and biliary secretions away from the proximal small intestine resulted in rapid increases in pancreatic size and protein content in adult rats. The effect was detectable as early as 10 days postsurgery. Differential changes in pancreatic enzymes were evident after bypass. The concentration of trypsinogen remained stable while amylase concentrations showed a marked decrease. Total pancreatic trypsinogen content, however, was increased, while amylase content remained similar to controls. Feeding bypassed rats with chows containing various pancreatic and biliary supplements had no effect on the hyperplastic response of their pancreata. Trypsinogen and amylase levels in supplemented groups remained similar to the bypassed group fed nonsupplemented chow, with the exception of increases in trypsinogen concentration and content in the groups supplemented with bile and cotazyme plus bile acids. The adequacy of oral refeeding of pancreatic biliary components was supported by its effectiveness in restoring mucosal enterokinase activity and trypsin levels in segment 1. However, there was no correlation between tryptic activity in the contents of the bypassed segment and the eventual pancreatic weight. These results indicate that factors other than those supplemented in this study are required in maintaining the steady state of pancreatic growth in normal rats.
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PMID:Enteral feedback control of pancreatic hypertrophy: the role of pancreatic biliary secretions. 394 29

The activation of trypsinogen to trypsin in the small intestine can occur by the action of enterokinase or, alternatively, as an autocatalytic process catalysed by trypsin itself. We have found that bile salts and human bile cause a significant enhancement of the autocatalytic activation of trypsinogen. This effect is dependent on the calcium ion concentration and is most marked around pH 5.4 and 7.8. An optimum concentration exists for each bile salt at which the greatest enhancement occurs. At this concentration, certain bile salts have been shown to produce activation effects of up to 55-fold. It is suggested that this activation of the autocatalytic process by bile plays an important role in protein digestion in the small intestine, since it has been shown previously that duodenal trypsin levels are abnormally low in patients with an impairment of bile secretion.
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PMID:Enhancement of the autocatalytic activation of trypsinogen to trypsin by bile and bile acids. 398 21

The effect of 3 purified trypsin inhibitors and 4 legume seed extracts on teh trypsins and chymotrypsins of the activated pancreata of 11 animal species, including man, was measured. The activation was performed by either homologous enterokinase or by bovine trypsin. Several trypsinogens were not activated by the latter. Rabbit trypsin was the most sensitive to all inhibitor preparations, while the human trypsin was the most resistant, except to the black bean extract. The response of the chymotrypsins was more variable and those of capybara and rabbit showed extreme sensitivity. Considerable differences between the extracts of black and white garden beans, both Phaseolus vulgaris, with respect to their reactivity toward different animal enzymes were detected. No relation between relative pancreas weight and susceptibility toward soybean trypsin inhibitor could be observed.
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PMID:Inhibition of trypsins and chymotrypsins from different animal species: a comparative study. 405 91

An ideal canine model of anomalous pancreaticobiliary ductal union, similar to a human anomaly, was devised. Direct anastomosis of the dorsal pancreatic duct and the choledochus was employed (dorsal pancreaticocholedochostomy). The ventral pancreatic duct was not manipulated. Cylindrical choledochal dilatation results in 13 out of 20 adult dogs and in 4 out of 6 puppies. Dilatation of the intrahepatic biliary tree and thickening of the choledochal wall in a hepatic direction were observed in high ratio among adult dogs. Puppies had less dilatation. The activation of pancreatic enzymes was studied in bile containing pancreatic juice. The proteolytic enzymes, trypsin and elastase were proven to be activated in the bile without the presence of enterokinase in the pancreaticocholedochostomy model. This would be the cause of the ill effects of refluxed pancreatic juice into bile in anomalous pancreaticobiliary ductal union.
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PMID:Experimental analysis of the ill effect of anomalous pancreaticobiliary ductal union. 617 6

Porcine rotaviral infectivity for continuous porcine kidney (PK-15) cells was enhanced by incorporation of pancreatic endopeptidases into the cell culture maintenance medium. Marked enhancement of infectivity was induced by trypsin, whereas elestase and alpha-chymotrypsin enhanced infectivity to a lesser extent. Bacterial protease also induced some enhancement of porcine rotaviral infectivity. A synergistic enhancement of porcine rotaviral infectivity was noticed with trypsin and alpha-chymotrypsin combined. Porcine rotaviral infectivity was not affected by incorporation of alpha-amylase, alkaline phosphatase, beta-galactosidase, carboxypeptidase-A, deoxyribonuclease, enterokinase, lipase, or ribonuclease into the maintenance medium.
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PMID:Porcine rotaviral infection of cell culture: effects of certain enzymes. 624 64

We report a 13-mo-old patient with isolated congenital enterokinase deficiency and review the clinical features, diagnostic approach, and management of all 8 reported patients. Our patient presented with failure to thrive, diarrhea, and hypoproteinemia since birth. A normal sweat chloride with small intestinal histology, and nondetectable trypsin activity in the duodenal fluid should alert the physician to the possibility of isolated enterokinase deficiency. All reported patients, including our own, responded favorably to pancreatic enzyme replacement. In vitro studies of the small intestinal mucosal biopsy specimen suggest that enterokinase deficiency at least in part is due to altered enzymes with low enterokinase activity.
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PMID:Isolated congenital enterokinase deficiency. Recent findings and review of the literature. 634 1

The interrelationship between trypsin/trypsinogen and enterokinase (EK) was studied in rats following induction of trypsinogen hypersecretion by various agents. Both soybean trypsin inhibitor and para-aminobenzamidine increased intraluminal tryptic activities to a level about twice that found in the control rats. This resulted in an increase in the mucosal and the intraluminal contents of EK in the rat small intestine. On the other hand, in cholecystokinin-treated rats, although there was an increase of intraluminal trypsin, the increase was about 80% less than in the inhibitor-fed rats. Under this condition, there was no effect on the mucosal or the intraluminal EK. These results suggested that substantial increase in intraluminal trypsin/trypsinogen levels (two-fold over control) will increase the mucosal and the intraluminal concentrations of EK in the rat small intestine. Our observation extends previous reports that a decreased level of trypsin/trypsinogen, such as in pancreatic insufficiency, leads to a decrease in mucosal EK. These observations, when taken together, strongly support the modulating role of intraluminal trypsin/trypsinogen levels in controlling the EK concentrations in the small intestine.
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PMID:Induction of enterokinase in the rat small intestine following hypersecretion of trypsinogen by chronic trypsin inhibitor feeding. 637 52

Mouse pancreatic proteases were analyzed by one- and two-dimensional electrophoresis. Active proteases that existed in the luminal fluid were separated into at least eight bands in 8% polyacrylamide gel. Pancreatic proteases activated by intestinal extract were separated into at least seven bands. The mobilities of these bands were exactly the same as those of proteases in the luminal fluid except for those of the most cathodal band. Two kinds of trypsin (Try-I group and Try-II) and one kind of chymotrypsin (Chy-I) were determined by specific and nonspecific protease staining. Try-I group and Try-II were derived from different trypsinogens (Try G-I group and Try G-II), whereas Chy-I was derived from a single chymotrypsinogen (Chy G). Although Try G-II was activated by both intestinal extract and by bovine trypsin, Try G-I group activated only by intestinal extract. Intestinal-activating factors were analyzed by two-dimensional electrophoresis. Mouse enterokinase (enteropeptidase EC 3.4.4.8), which can activate bovine trypsinogen, had a slow mobility. In the intestine of the mouse there are several activating factors in addition to enterokinase. Although it is unclear what intestinal-activating factors can activate Chy G, there is a factor that can convert chymotrypsinogen into chymotrypsin directly. These data suggest that intestinal-activating factors play an important role in the activating mechanisms of mouse pancreatic zymogens.
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PMID:Electrophoretic analysis of pancreatic proteases and zymogen-activating factors in the mouse. 637 96


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