Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study evaluates the effect of atropine and of the cholecystokinin receptor antagonist loxiglumide on feedback regulation of basal pancreatic secretion in 6 healthy volunteers. The intraduodenal instillation of the protease inhibitor camostate reduced enzymatic activities of trypsin and chymotrypsin by 80%. This was accompanied by a strong increase in amylase and lipase output. The intravenous infusion of atropine (5 micrograms/kg.h) completely abolished the stimulatory effect of camostate on enzyme output. The infusion of loxiglumide (10 mg/kg.h) caused no changes in camostate-induced stimulation of enzyme output. Plasma levels of cholecystokinin were not altered after intraduodenal instillation of camostate whether atropine, loxiglumide, or saline were infused. We suggest that the protease inhibitor camostate, by inhibition of the enzymatic activity of trypsin and chymotrypsin, interferes with feedback regulation of basal pancreatic secretion in humans, and this mechanism is predominantly mediated by the cholinergic system.
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PMID:Differential effects of atropine and a cholecystokinin receptor antagonist on pancreatic secretion. 264 76

Differences in pancreatic responses and CCK release to intragastric administration of a synthetic protease inhibitor (camostate) were examined in young (6-mo) and old (26-mo) female rats. When rats were sacrificed 1 hour after camostate administration (100 mg/kg), plasma CCK concentration significantly increased in both age groups and was significantly higher in young rats than in the old. Acute pancreatic responses to camostate were attenuated in old rats, compared with the young. On the other hand, 5-day administration of camostate (100 mg/kg, twice a day) increased pancreatic wet weight, chymotrypsin concentration and content in pancreas in both age groups, whereas lipase content did not increase in old rats although it significantly increased in young rats. Plasma CCK concentrations were not significantly different between young and old rats. It is concluded that the acute response of CCK release to camostate is attenuated in old rats, but the capability of chronic pancreatic adaptation of chymotrypsin content to camostate is well maintained in old rats.
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PMID:Effects of trypsin inhibitor (camostate) on pancreas and CCK release in young and old female rats. 273 9

Hedgehog plasma was separated by gel filtration on Sephacryl S-200, the fractions resolved by electrophoresis and the electrophoretograms characterized for collagenase, papain and plasmin inhibiting activities with the high mol. wt substrate casein. The three inhibitors previously identified as alpha 2-, alpha 2-beta- and beta-macroglobulins were found to inhibit all three proteases. These were the only collagenase inhibitors found in plasma. Hedgehog alpha 2-chymotrypsin inhibitor and beta-protease inhibitor were both found to also inhibit papain. Three new inhibitors specific for papain (gamma-, alpha 2- and alpha 1-cysteine protease inhibitors) and one for plasmin (alpha 2-antiplasmin) were also found, bringing the number of protease inhibitors in hedgehog plasma to 14. Immunological cross-reactivity as studied by immunoelectrophoresis showed homology between hedgehog alpha 2-macroglobulin and rat murinoglobulin I and between hedgehog alpha 2-antithrombin and rat antithrombin III.
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PMID:Further studies of plasma protease inhibitors in the hedgehog, Erinaceus europaeus; collagenase, papain and plasmin inhibitors. 288 40

This workshop was organized to discuss the current state of research on anticarcinogenic protease inhibitors with regard to their potential use as human cancer chemopreventive agents. Previous studies have indicated that protease inhibitors can be powerful anticarcinogenic agents for animals and cells in culture and that human populations known to have high concentrations of protease inhibitors in the diet have low overall cancer mortality rates. In the workshop discussions, emphasis was placed on certain dietary protease inhibitors, such as the soybean-derived Bowman-Birk inhibitor and chymotrypsin inhibitor 1 from potatoes and some of the highly purified protease inhibitors of microbial origin provided by the Japan Society for the Promotion of Science, which have already been shown to contain anticarcinogenic activity in laboratory studies. Potential adverse side effects of dietary protease inhibitors were also considered, specifically, their possible effects on the pancreas and in causing decreased growth rates in young organisms. It was pointed out that the pancreata of a few species, notably rats and chicks, are extraordinarily sensitive to dietary protease inhibitors. Rats fed diets containing high concentrations of soybean-derived protease inhibitors (raw soy flour) had enlarged pancreata; increased pancreatic growth is thought to accelerate cancer development in the pancreas. The effect of raw soy flour on the growth of the rat pancreas has not been shown to occur in most other species tested (examples include hamsters, mice, dogs, pigs, and monkeys) and is not expected to occur in humans. There is no evidence that dietary protease inhibitors have adverse effects on the human pancreas. In fact, it has been observed that human populations with high levels of dietary protease inhibitors have decreased rates of pancreatic cancer. Dietary concentrations of protease inhibitors which have been shown to be anticarcinogenic have not produced decreased growth rates in animals or any type of pancreatic pathology. In general, there was a high level of enthusiasm at the workshop for the further development of protease inhibitors as chemopreventive agents. Recommendations for future research include: (a) research and development of sources of protease inhibitors; (b) analysis of human foods for protease inhibitor content; (c) evaluation of cancer incidence data in relation to protease inhibitor content and characteristics in the diet of human populations; (d) animal studies on the efficacy of protease inhibitors in cancer prevention; and (e) studies on the mechanism of action of anticarcinogenic protease inhibitors.
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PMID:Workshop report from the Division of Cancer Etiology, National Cancer Institute, National Institutes of Health. Protease inhibitors as cancer chemopreventive agents. 291 Apr 69

Plasmin was recently reported to inhibit platelet aggregation. We report here on the interaction of plasmin with the adenylate cyclase system of human platelets. Human plasmin caused a dose- and time-dependent increase in adenylate cyclase activity when added to a crude platelet membrane preparation. Both basal and prostaglandin E1-stimulated adenylate cyclase activity doubled in presence of plasmin. This stimulatory activity was shared by papain and alpha-chymotrypsin, but not by thrombin which displayed a slightly inhibitory effect. Plasmin not only stimulated platelet adenylate cyclase activity, but also suppressed the GTP-dependent alpha 2-adrenergic inhibition, thereby producing a five- to six-fold increased activity measured in the presence of adrenaline and GTP. These effects of plasmin on the adenylate cyclase system were suppressed by the addition of the protease inhibitor leupeptin, and of soybean trypsin inhibitor, indicating that proteolysis mediated these effects. We also examined the adenylate cyclase activity in membranes prepared from intact platelets incubated with increasing doses of plasmin. Incubation of platelets with plasmin concentrations as low as 0.25 mg/ml resulted in an irreversible increase in membrane adenylate cyclase activity and suppression of the adrenaline-mediated inhibition of enzyme activity. These results suggest that the proteolytic stimulating effect of plasmin on the platelet adenylate cyclase system may account for the inhibition of platelet aggregation.
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PMID:Plasmin: a possible physiological modulator of the human platelet adenylate cyclase system. 295 Oct 52

Pancreatic secretion and plasma cholecystokinin (CCK) and secretin levels were measured in 10 healthy volunteers after application of a serine protease inhibitor (camostate) to study the mechanism of feedback regulation. Camostate produced a strong inhibition of trypsin and chymotrypsin activity in duodenal juice for 1 h. This was accompanied by an increase in duodenal aspirate volume and pancreatic enzyme secretion under both basal and secretin-stimulated conditions. Due to inhibition of tryptic activity, survival of lipase activity in duodenal juice was prolonged. In control experiments we ruled out that the volume and the pH of the solution were responsible for stimulation of pancreatic secretion. The protease inhibitor did not alter pancreatic secretion, which was stimulated by a test meal. Plasma levels of CCK and secretin were not changed after duodenal perfusion of camostate. These observations suggest that trypsin and chymotrypsin are involved in feedback regulation of pancreatic secretion in man which is, however, not mediated by CCK or secretin.
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PMID:Stimulation of pancreatic secretion in man by a protease inhibitor (camostate). 313 Feb 67

A low molecular weight protein protease inhibitor was purified from Japanese horseshoe crab (Tachypleus tridentatus) hemocytes. It consisted of a single polypeptide with a total of 61 amino acid residues. This protease inhibitor inhibited stoichiometrically the amidase activity of trypsin (Ki = 4.60 X 10(-10) M), and also had inhibitory effects on alpha-chymotrypsin (Ki = 5.54 X 10(-9) M), elastase (Ki = 7.20 X 10(-8) M), plasmin, and plasma kallikrein. However, it had no effect on T. tridentatus clotting enzyme and factor C, mammalian blood coagulation factors (activated protein C, factor Xa and alpha-thrombin), papain, and thermolysin. The complete amino acid sequence of this inhibitor was determined and its sequence was compared with those of bovine pancreatic trypsin inhibitor (BPTI) and other Kunitz-type inhibitors. It was found that the amino acid sequence of this inhibitor has a high homology of 47 and 43% with those of sea anemone inhibitor 5-II and BPTI, respectively. Thus, this protease inhibitor appeared to be one of the typical Kunitz-type protease inhibitors.
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PMID:Purification and amino acid sequence of Kunitz-type protease inhibitor found in the hemocytes of horseshoe crab (Tachypleus tridentatus). 330 64

Protease and antiprotease activities were estimated in nasal secretions from patients with chronic sinusitis and nasal allergy, using [3H]-casein as substrate. In the purulent nasal secretions, strong protease activity was measured, but there was less activity in the allergic nasal secretions. In contrast, trypsin inhibitory activity in allergic nasal secretions was much higher than in nasal secretions from the patients with chronic sinusitis. A protease inhibitor was partially isolated from nasal secretions of the nasal allergic patients by Sephadex G-150 gel chromatography and characterized. This protease inhibitor has an apparent molecular weight of 10,000 D, determined by SDS-polyacrylamidegel electrophoresis. It depresses the activities of bovine pancreatic trypsin, bovine pancreatic chymotrypsin and proteases in nasal purulent secretions, whereas it does not inhibit porcine pancreatic elastase, papain, or human plasmin.
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PMID:A protease inhibitor from human allergic nasal secretions. 332 29

Specific monoclonal antibodies against the active sites of two genetically engineered pancreatic secretory trypsin inhibitor (PSTI) variants (PSTI 0 and PSTI 4) were produced. The protease inhibitors PSTI 0 and PSTI 4 differ only by three amino acid substitution at their active sites. PSTI 0 inhibits trypsin, whereas PSTI 4 inhibits human granulocyte elastase and chymotrypsin. Immunization was performed in vitro with a synthetic heptapeptide that covers the mutated region of the protein. For this purpose in vitro culture conditions for the production of specific monoclonal antibodies against synthetic peptides were improved. The monoclonal antibodies obtained react specifically with the corresponding protease inhibitor variant. Competition experiments with trypsin and human elastase demonstrate that the protease displace the monoclonal antibody from the active site of PSTI 0 and PSTI 4 respectively.
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PMID:Production of specific monoclonal antibodies against the active sites of human pancreatic secretory trypsin inhibitor variants by in vitro immunization with synthetic peptides. 340 53

Electrophoretic examination (isoelectric focusing and polyacrylamide gel electrophoresis) of 157 plasmas from a Kangaroo Island population of tammar wallabies (Macropus eugenii) resulted in the identification of five putative condominant protease inhibitor alleles, F, I, M, P and S, which exhibited microheterogeneity due to variable terminal sialic acid content. The frequencies of the five alleles in this population were 0.041(F), 0.682(I), 0.194(M), 0.073(P) and 0.010(S). The proteins had isoelectric points in the pH range 3.94-4.38, Mr of 60,500 to 66,000 and were identified as protease inhibitors by their abilities to inhibit both trypsin and chymotrypsin. Protein blotting of the denatured proteins demonstrated cross reaction with antiserum to human alpha 1-protease inhibitor.
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PMID:Tammar wallaby plasma protease inhibitory (Pi) proteins. 345 36


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