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)

The purification and characterization of three pancreatic trypsinogens A1, A2, and A3, from the African lungfish, Protopterus aethiopicus, is reported. These zymogens are activated by trypsin, by enterokinase, by an acid protease from Aspergillus oryzae, and by autoactivation. The three trypsinogens contain the same amino-terminal amino acid sequence, beginning with the activation peptide Leu-Pro-Leu-Glu-Asp-Asp-Lys-. Like the activation peptide of the previously characterized trypsinogen B [Reeck, G. R., & Neurath, H. (1972) Biochemistry 11, 503] of the same organism, it lacks the tetraaspartyl sequence characteristic of other vertebrate trypsinogens. Two of the corresponding lungfish trypsins were found to have identical amino-terminal sequences for at least 27 residues. These data suggest that the three enzymes are allelic variants. In contrast, the amino acid sequences differ sufficiently from that of trypsinogen B of the same organism to indicate that trypsinogens A and B are the products of different gene loci.
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PMID:Isolation and amino-terminal sequence analysis of a new pancreatic trypsinogen of the African lungfish Protopterus aethiopicus. 91 66

The effect of heparin on the activation of trypsinogen by enterokinase and on trypsin activity has been investigated. Proteolytic activity of trypsin has been determined using caseinolytic method. It has been found that heparin inhibits trypsinogen activation only when it is preincubated with proenzyme before introduction of enterokinase to the tested system. In these experimental conditions heparin in final concentrations from 1 to 20 U/ml exhibits inhibitory effect diminishing trypsinogen activation to about 65% initial activity and in higher concentrations only to 50%. Heparin introduced to the tested system simultaneously with enterokinase or to the active trypsin did not appear evident inhibitory effect.
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PMID:The inhibitory effect of heparin on trypsinogen activation with enterokinase. 93 May 38

The interrelationship of enterokinase and trypsin activities were investigated in 133 infants and children with a variety of gastrointestinal and pancreatic disorders. Fourteen patients with diarrhea and grade II mucosal injury revealed a significant (P less than 0.01) reduction of enterokinase, trypsin, and disaccharidase activites as compared to 59 children with normal mucosa. Nine patients with cystic fibrosis and pancreatic insufficiency had normal mucosal enterokinase activity and elevated intraluminal enterokinase activity with very low or no trypsin activity. Patients with hypoproteinemia and gastrointestinal protein loss, associated with intestinal lymphangiectasia (4 patients) and intestinal lymphoid nodular hyperplasia (3 patients), had normal or insignificant decrease of enterokinase and trypsin activities. In patients with steatorrhea, a normal sweat test, normal intestinal mucosa, and absent trypsin activity, two entities were defined. One group (3 patients) was diagnosed as Schwachman-Diamond syndrome with pancreatic insufficiency and normal mucosal and intraluminal enterokinase activity. The second group (2 patients) with absent mucosal and intraluminal enterokinase activity and normal lipase and amylase activities was diagnosed as congenital enterokinase deficiency.
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PMID:Enterokinase and trypsin activities in pancreatic insufficiency and diseases of the small intestine. 94 55

A method is described for the purification of human enterokinase from accumulated duodenal fluid by affinity chromatography using p-aminobenzamidine as the ligand. Resolution was greatest when glycylglycine was substituted as the spacer arm. Purification was not a one-step procedure, and some contamination, principally by the alpha-glucosidases, remained. Their removal was completed by immunoadsorption using antisera raised to enterokinase-free material containing these enzymes, prepared as a by-product of the purification procedure. The final preparation had an activity of 4260 nmol of trypsin/min per mg and was free of other enzymic activity tested. Amino acid and sugar analyses of the highly purified enzyme indicated an acidic glycoprotein containing 57% sugar (neutral sugars 47%, amino sugars 10%). The apparent mol.wts. and Stokes radii of human and pig enterokinase were 296 000 and 316 000, and 5.65 and 5.78 nm respectively. Two isoenzymes were identified for human enterokinase and three for the pig enzyme. Human enterokinase demonstrated a resistance to reduction of disulphide linkages and to sodium dodecyl sulphate binding, which may be related to the need for it to retain its integrity in the digestive environment of the upper small intestine. Antisera to highly purified pig and human enterokinases specifically inhibited enterokinase activity. Immuno-inhibition of intestinal aminopeptidase, maltase and glucoamylase by homologous antisera was not observed.
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PMID:The purification of human enterokinase by affinity chromatography and immunoadsorption. Some observations on its molecular characteristics and comparisons with the pig enzyme. 94 36

Deficiency of intestinal enterokinase results in failure to thrive, diarrhoea, anaemia, hypoproteinaemia and oedema. A case arising in the neonatal period is described, in which several of the characteristic features were lacking. Difficulties encountered in the diagnosis and methods of assay are discussed.
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PMID:Intestinal enterokinase deficiency. 96 14

In this study the influence of 14 antibiotics, 12 of them orally applicable, on human enterokinase was investigated. The effects of these substances on the activities of human disaccharidases were also examined. The enterokinase activity is more sensitive to the studied antibiotics than is human lactase, saccharase or isomaltase. Unphysiologically high concentrations of penicillins, cephalexin and chloramphenicol (10(-2) Mol/l) inhibited enterokinase, tetracycline (doxycycline) in a dose of 10(-3) m reduced the activity of this enzyme by 50%, neomycinsulphate and the sulphates of polymyxin B and E have no effect on the disaccharidases. On the contrary, these substances are the best inhibitors of enterokinase among the tested antibiotics. Neomycin or polymyxin (10(-4) Mol/l) causes a 50% inhibition of a physiological quantity of this enzyme. Therapeutic doses of both antibiotics may reduce the enterokinase activity by 70% to 90%, while the activity of trypsin is not affected unless a concentration greater than 10(-2) m is used. The inhibition is not only caused by the anion (SO4) of these antibiotics, since sulphates reduce the enterokinase only in concentrations higher than 10(-3) Mol/l in man. The mechanism of inhibition is not effected by binding cholic acids under test conditions. Both polymyxin and neomycin inhibit the enterokinase activity with and without glycodeoxycholic acid. Further studies showed that the type of inhibition is competitive in both cases. The inhibition constant K2 of neomycin-B-sulphate is 8.7X10(-5) Mol/l, of polymyxin-E-sulphate 8.6X10(-5) Mol/l. The inhibition type of penicillins, cephalosporins and doxycycline is noncompetitive, thus contrasting that of neomycin and polymyxin.
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PMID:[The influence of orally applicable antibiotics on the activities of human enterokinase and disaccharidases (author's transl)]. 98 20

Rat pancreatic juice (RPJ) reduced the mean uptake of 57CoB12 bound to rat intrinsic factor (IF) by perfused rat intestinal segments from 30.1 +/- 2.4 (pg 57CoB12 per cm intestine +/- S.E.M.) to 26.7 +/- 2.4 (p less than 0.05). RPJ activated with enterokinase reduced the uptake from 22.8 +/- 2.8 to 16.1 +/- 1.9 (p less than 0.05). RPJ also reduced the uptake from 15.8 +/- 2.3 to 8.3 +/- 2.0 (p less than 0.01) in segments from partially pancreatectomized rats. Rat bile abolished the inhibitory effect of RPJ. The results indicate that in the absence of bile the exocrine pancreatic secretion is capable of inhibiting the intestinal uptake of vitamin B12.
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PMID:Inhibitory effect of pancreatic juice on the intestinal uptake of vitamin B12. 99 36

Rare earths were found to be powerful inhibitors of enteropeptidase-catalyzed (enterokinase, EC 3.4.21.9) activation of trypsinogen. Inhibition was complete at a La3+ concentration of 12.5-10(-6) M in the assay system used and still detectable at a concentration of 1.25-10(-6) M. Inhibition was observed with all lanthanides tested. No significant differences between individual metals could be established under the conditions of the inhibition assay. Increasing ionic strength decreased enzyme activity and progressively diminished the inhibitory effect of rare earth ions suggesting an electrostatic basis for the mechanism of this inhibition. La3+ did not significantly affect enteropeptidase-mediated hydrolysis of N-benzoyl-L-arginine ethyl ester. Its inhibitory effect on activation of trypsinogen by enteropeptidase, therefore, must be attributed to interaction with the zymogen rather than the enzyme. Kinetic measurements show that inhibition by rare earths is noncompetitive in nature. Binding of lanthanides to the tetraaspartyl sequence near the aminoterminus of trypsinogen may prevent this group from interacting with a critical specificity subsite on the enzyme.
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PMID:The effect of lanthanide ions on enteropeptidase-catalyzed activation of trypsinogen. 100 24

The experiments on dogs have shown that during 3-5 weeks after resection of 1/3 and 2/3 of the pancreas the total amount of the excreted intestinal juice and the content of proper enteric enzymes in it (enterokinase, alkaline phosphatase and saccharase) are decreased. According to the author's data the activity of intestinal juice amylase and lipase being enzymes mostly of the pancreatic origin, transferred in the small intestine from blood, is enhanced due to impairment of the histo-hematic barrier in the region of the resected pancreatic stump. 2-3 months following resection of 2/3 of the pancreatic gland the amount of excreted intestinal juice was nearly unchanged, but the content of proper enteric enzymes was somewhat increased, as compared with background indices.
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PMID:[Secretory activity of the small intestine after resection of the pancreas]. 101 22

The two human anionic trypsinogens 1 and 2 were purified from human pancreatic juice by gel filtration on Sephadex G-100 and by chromatography on DEAE-cellulose. After activation of their respective zymogens by porcine enterokinase, human trypsins 1 and 2 were studied for their reaction with a wide variety of proteinase inhibitors. Kunitz pancreatic trypsin inhibitor and human pancreatic secretory trypsin inhibitor completely inhibited both human trypsins at a stoichiometric inhibitor-to-enzyme ratio of one to one. In contrast, bovine pancreatic secretory trypsin inhibitor (Kazal's inhibitor) failed to inhibit either human trypsin. The inhibition of both human trypsins by porcine pancreatic secretory trypsin inhibitor was demonstrated. The reactions of the trypsins with chicken ovomucoid, Ascaris lumbricoides (type suis), human sperm and blood plasma trypsin inhibitors were studied. The most striking difference between the two human trypsins was the reaction with soybean trypsin inhibitor (Kunitz). Trypsin 2 was completely inhibited in a one-to-one molar ratio while trypsin 1 was poorly inhibited. The presence of a prekallikrein in human pancreatic juice is discussed.
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PMID:The two human trypsinogens. Inhibition spectra of the two human trypsins derived from their purified zymogens. 107 68


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