Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.9 (enterokinase)
 675 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A genetically conditioned mouse model of exocrine pancreatic insufficiency (epi) has been used to study the effect of the absence of lumenal proteases on small intestinal mucosal proteins. The small bowel was divided into eight equal segments. Enzyme activity was increased only in the first three segments in the case of maltase, sucrase, and lactase (all mol wt above 200,000). Alkaline phosphatase (mol wt 145,000), trehalase (mol wt 95,000), and peptidase (mol wt 175,000) activities were unaffected in proximal segments from epi mice. Proximal brush border proteins were identified and measured quantitatively by sodium dodecyl sulfate acrylamide gel electrophoresis. Those enzymes with increased activity were associated with increased amounts of protein in epi mice. Double labeled studies of protein turnover revealed a longer half-life for large brush border proteins (mol wt above 175,000) in epi mice than in normal mice. Enterokinase activity (a marker for duodenal mucosa) was nearly absent from the duodenum of epi mice. Receptors for the intrinsic factor-vitamin B12 complex (markers for ileal mucosal) were present in the ileum equally in normal and in epi mice. Enterokinase activity can be induced in epi mice by feeding its substrate trypsinogen, but not by trypsin or chymotrypsinogen. Epi mice thus retain the ability to synthesize enterokinase. Pancreatic proteases play an important role in the turnover of certain large mucosal proteins and in the induction of enterokinase.
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PMID:Effect of exchange exocrine pancreatic insufficiency on small intestine in the mouse. 20 83

A modification of Weiser's (1973) cell isolation method was used in order to study the developmental pattern of various intestinal enzyme activities in villus and crypt cells of normal rats from 5 days after birth until 8 weeks. Alkaline phosphatase and enterokinase activities were always located in the upper villus zone during postnatal development. Enterokinase activity was higher in the upper villus cells during the third week of life than after this period. Aminopeptidase activity was located in the crypt cells during the first week, its maximum activity remained in this area until the third week. At this time, sucrase activity appeared in the crypt cells, then aminopeptidase and sucrase activities rose to the villus zone during the fourth week. Amylase activity was detected along the entire crypt-villus axis 5 days after birth, reaching maximum activity in crypt cells at the end of the first week and in the upper villus cells after the fourth week. In contrast with the other enzymes studied almost all amylase activity was soluble in the youngest animals whereas at weaning most of the activity appeared in a particulate form in the villus cells. But in the crypt cells the ratio between particulate and soluble form remained unchanged until the adult stage. Various hypotheses are advanced to explain the patterns of evolution of the different enzymes.
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PMID:Intestinal enzymes activities in isolated villus and crypt cells during postnatal development of the rat. 83 93

The quantitative release of enterokinase from isolated rat enterocytes following treatment with taurocholate-taurodeoxycholate, papain, chymotrypsin, elastase, carbamylcholine, and cholecystokinin-octapeptide was examined. Alkaline phosphatase and lactate dehydrogenase activities were evaluated simultaneously to check for specificity. Bile salts promoted a concentration-dependent release of all enzymes. Concomitantly, bile salts also led to cell destruction in proportion to the amount of enzymes released. Proteases caused the release of enterokinase and alkaline phosphatase with no concomitant increase of lactate dehydrogenase or cell lysis. At equal concentrations, papain released more enzymes than chymotrypsin and elastase. Chymotrypsin and elastase, however, led to higher ratios of enterokinase to alkaline phosphatase found in the media and suggested a selective release of enterokinase (EK) over that of alkaline phosphatase. Bile salts and pancreatic proteases together seem to have an additive effect of the release of EK. Carbamylcholine and cholecystokinin-octapeptide had no effect on enzyme release. These results suggested that pancreatic proteases are involved in the release of enterokinase by a selective action. Bile salts may also play a role through a nonselective detergent effect.
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PMID:Physiological factors controlling release of enterokinase from rat enterocytes. 390 6

The effect of severe malnutrition and protein deficiency on small intestine has been documented, but the literature on the effect of mild-to-moderate protein-energy malnutrition (PEM) on small intestine is scant. Mild-to-moderate PEM is most prevalent in India. Twenty-four young rhesus monkeys weighing 1.5-2.0 kg were divided into two groups, control and experimental. Mild-to-moderate PEM was induced in the experimental group by giving half of the required normal diet providing 2.42 g protein.kg-1.day-1 and 55 kcal.kg-1.day-1. Body weight, serum protein, and D-xylose were measured before starting the experiment, at PEM stage, and after rehabilitation. Experimental monkeys representing group I were killed after a 25-30% reduction in body weight along with control group 1 animals at 12 wk. The rest of the experimental animals were rehabilitated for another 10-12 wk and killed along with their respective controls (control group 2). Brush-border membrane vesicles were prepared from three parts of the small intestine. Viable vesicles were used for the uptake of [U-14C]L-proline. Alkaline phosphatase and enterokinase were also measured. Uptake of L-proline amino acid and the activity of both enzymes were found to be decreased significantly in the PEM group; a D-xylose test was abnormal. All animals recovered after rehabilitation. These results indicate that even mild-to-moderate malnutrition affects the absorptive and digestive capacity of the brush border of the small intestine, which reversed back on rehabilitation.
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PMID:Mild-to-moderate malnutrition and small intestine of young rhesus monkeys. 854