Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effect of disruption to the epithelium of intact porcine bronchi was examined by comparing the responsiveness to agonists applied to the adventitial and luminal surfaces. The development of smooth muscle tone was measured as an increase in pressure in an isovolumic bronchial segment of approximately 2 mm i.d. The reactivity and sensitivity to acetylcholine (ACh) introduced intraluminally was greatly attenuated when compared with adventitial addition. 2. Luminal exposure to K+ and vanadate (VO3-) had little effect compared with strong responses obtained by adventitial application. 3. Intraluminal exposure to trypsin, chymotrypsin and elastase (1 mg/mL) selectively augmented both the sensitivity and the reactivity to the luminal addition of ACh, K+ and carbachol. 4. Mechanical removal of the epithelium produced a 716-fold increase in sensitivity to ACh introduced luminally but had no effect on ACh applied adventitially. 5. The inhibitory effects of luminally introduced isoprenaline on electrical field stimulation responses were also significantly potentiated in segments stripped of epithelium. 6. The evidence presented here indicates that the responsiveness of in vitro airways segments is highly influenced by the epithelial layer, which acts most prominently as a barrier inhibiting the penetration of luminally introduced agonists.
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PMID:Epithelial disruption by proteases augments the responsiveness of porcine bronchial segments. 147 93

Luminal proteolytic activity (PA) of different colonic segments was ascertained in animals subjected to pancreatic duct ligation (PDL) and in control rats. The PDL rats revealed a significant PA reduction in the cecum, proximal colon (P < 0.01), and distal colon (P < 0.005). Proteolytic activity, trypsin, and chymotrypsin activity in control rats diminished progressively from the cecum to the distal colon. Conversely in PDL rats, we found maximal PA in distal colon. The conclusion is drawn that a significant proportion of colonic proteolytic activity can be attributed to pancreatic proteases with a maximal contribution at cecum level.
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PMID:Colonic proteolysis following pancreatic duct ligation in the rat. 780 12

Luminal bile-pancreatic juice (BPJ) is involved in the induction of pancreatic proteases in rats fed a high-protein diet. Recently, we have demonstrated that a BPJ-independent mechanism is responsible for enhancement of pancreatic secretion after feeding of a dietary protein in chronic BPJ-diverted rats. The aim of the present study was to explore the existence of a BPJ-independent mechanism during adaptation of the exocrine pancreas to dietary protein. Rats, whose BPJ was diverted into the ileum through a common bile-pancreatic duct catheter for 5 days (PBD rat), were fed a fat-free diet containing 25% or 60% casein for 3 days. Messenger RNA levels for pancreatic enzymes, cholecystokinin, and secretin in the jejunal mucosa were evaluated by northern blotting method. Pancreatic trypsin and chymotrypsin activities and mRNA levels of their zymogens were higher in PBD rats than in rats whose diverted BPJ was returned into the duodenum (PBD returned rat). In the PBD groups, pancreatic protease activities were further increased by 3-day feeding of a high-protein diet without changes in mRNA levels of these proteases. Cholecystokinin mRNA was increased after feeding of a high-protein diet in the PBD rats. These results indicate that pancreatic proteases are induced by feeding a high-protein diet by a mechanism independent of luminal BPJ, which is associated with an increase in intestinal cholecystokinin mRNA level.
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PMID:Bile-pancreatic juice-independent increases in pancreatic proteases and intestinal cholecystokinin by dietary protein in rats. 945 41

A protein (bovine serum albumin: BSA) and a peptide (luteinizing hormone releasing hormone: LHRH) were used to evaluate proteolytic activity in the intestine of common brushtail possums (Marsupiala, Trichosurus vulpecula). Luminal and mucosal extracts were isolated from the duodenum, jejunum, ileum, caecum, proximal colon and distal colon, their protein content assessed and specific activities in metabolising LHRH and BSA determined in vitro. The degradation of LHRH by luminal extracts was compared with that by the pancreatic enzymes, chymotrypsin, trypsin, and elastase. The protein concentration (microg x mg-1) of mucosal extract in the duodenum was higher ( P<0.05) than in the proximal colon, but that of luminal extracts did not differ significantly between regions. Proteolytic activity of luminal extracts was greater ( P<0.01) in the jejunum and ileum than in the hindgut. In the small intestine, proteolytic activity of luminal enzymes far exceeded that of mucosal enzymes ( P<0.05). All three pancreatic enzymes hydrolysed LHRH, but chymotrypsin had the greatest activity. This study has demonstrated that, in possums, proteolysis occurs primarily in the small intestine through luminal enzymes, with chymotrypsin playing a major role. The possum hindgut contributes little to the metabolism of peptides and proteins, identifying it as a potential site to target for their absorption following oral delivery.
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PMID:Protein and peptide degradation in the intestine of the common brushtail possum (Trichosurus vulpecula). 1235 23