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)

Methoxypolyethylene glycols of 1900 daltons (PEG-1900) or 5000 daltons (PEG-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. Rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups (PEG-1900-catalase). The intravenous antiserum did not yield detectable antibodies against PEG-1900-catalase or native catalase, as determined by Ouchterlony and complement fixation methods, whereas the intramuscular antiserum contained antibodies to both PEG-1900-catalase and catalase. PEG-1900 did not react with either antiserum. Catalase was prepared in which PEG-5000 was attached to 40% of the amino groups (PEG-5000-catalase). This catalase preparation did not react with either antiserum. PEG-1900-catalase retained 93% of its enzymatic activity; PEG-5000-catalase retained 95%. PEG-5000-catalase resisted digestion by trypsin, chymotrypsin, and a protease from Streptomyces griseus. PEG-1900-catalase and PEG-5000-catalase exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections. No evidence was seen of an immune response to injections of the modified enzymes. Mice injected repetitively with PEG-5000-catalase remained immune competent for unmodieied catalase, and no evidence of tissue or organ damage was seen.
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PMID:Effect of covalent attachment of polyethylene glycol on immunogenicity and circulating life of bovine liver catalase. 1 7

Human and bovine alpha-thrombin cleaved at the B-chain by chymotrypsin generates catalytically competent zeta-thrombins, which are comprised of two noncovalently linked fragments: a 36-(human) or 49-(bovine) residue A-chain linked by a disulfide to B-chain residues B1-148 (zeta 1-thrombin) and B-chain residues B149-259 (zeta 2-thrombin). Human and bovine D-Phe-Pro-Arg-CH2-zeta- and PhMeSO2-zeta-thrombins were prepared by reaction of the active-site histidine (H-B43) and serine (S-B205) with PPACK and PMSF, respectively. Unfolding and dissociation of the noncovalently linked polypeptide chains of either human or bovine D-Phe-Pro-Arg-CH2-zeta- and PhMeSO2-zeta-thrombins in 4.5 M guanidine-HCl and refolding upon 30-fold dilution in 50 mM sodium phosphate buffer pH 6.5, 750 mM NaCl, 0.1% PEG resulted in biphasic generation of catalytic activity. The slow phase was eliminated in the presence of the competitive inhibitor benzamidine-HCl. Unfolding and refolding mixtures of the appropriate inactive precursors generated the active chimeric thrombins bovine zeta 1-thrombin:human zeta 2-thrombin and human zeta 1-thrombin:bovine zeta 2-thrombin. Human zeta 1-thrombin and zeta 2-thrombin were isolated, and, upon recombining, the isolated fragments refolded to generate catalytically competent zeta-thrombin with an active-site content, specific activity toward Chromozym-TH, and a specificity constant (kcat/Km) for FPA release from fibrinogen that were all within 60% of those of native alpha-thrombin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Catalytically competent human and bovine zeta-thrombin and chimeras generated from unfolded polypeptide chains. 130 87

Serum IgG has been covalently bonded to polyethylene glycols of either 2000 or 8000 molecular weight to produce immunoglobulin conjugates with 4.4-27.2% of primary amines bonded to polyethylene glycol. Polyethylene glycol immunoglobulin conjugates retain the ability, comparable to native IgG, to bind to a range of protein and microbial antigens, but have a reduced ability to bind to Fc receptors or to fix complement C3. When 6.8% or more of available primary amines are conjugated, IgG-PEG conjugates are impervious to trypsin, and at 14% or more conjugation, more resistant than native IgG to pepsin and chymotrypsin. We suggest that PEG-Ig conjugates may be useful for the oral treatment of various gastrointestinal diseases in which secretory humoral immunity is insufficient.
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PMID:Biological activities of polyethylene-glycol immunoglobulin conjugates. Resistance to enzymatic degradation. 150 Jul 28

The existence of negative feedback inhibition of human pancreatic enzyme secretion by proteases is controversially discussed. We have recently demonstrated that jejunal application of porcine pancreatic extracts, in a dose commonly used to treat digestive insufficiency, stimulated rather than inhibited, human pancreatic enzyme secretion. We have now studied the influence of duodenal application of high concentrations of either pure trypsin or porcine pancreatic extracts with trypsin-equivalent activity, on human pancreatic enzyme secretion. Twenty-three male volunteers were intubated with a gastric tube and a two-lumen jejunal tube to collect secretions separately via the first and third tubes and to perfuse either pure trypsin or porcine pancreatic extracts distal to the pylorus via the second tube. PEG-4.000 was continuously perfused via the second tube to correct for losses of volume. Volunteers received PEG alone during the first hour, phenylalanine during the second, PEG alone again during the third, and either phenylalanine together with trypsin or porcine pancreatic extracts during the fourth h. Activities of lipase, amylase, and chymotrypsin were measured in 15-min fractions. In addition, human lipase secretion was measured with an enzyme immunoassay, which does not crossreact with porcine lipase. Plasma cholecystokinin (CCK) was measured using a sensitive bioassay, which utilizes amylase release by isolated rat pancreatic acini. Perfusion of the duodenum with phenylalanine caused a statistically significant stimulation of enzyme secretion. This stimulation could be inhibited by high concentrations of pure trypsin. In contrast, application of porcine pancreatic extracts, which contained the equivalent activity of trypsin, caused further increases of lipase secretion when compared to phenylalanine alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of exogenous application of pancreatic extracts on endogenous pancreatic enzyme secretion. 172 24

We have evaluated the effects of porcine pancreatic extracts on human pancreatic secretion. Ten male volunteers were intubated with a 4-lumen jejunal tube to collect gastric and duodenal secretions separately via the first and third tube, to infuse PEG 4000 distal the pylorus via the second tube and to apply porcine pancreatic extracts via the fourth tube distal the ligament of Treitz. Pancreatic extracts were given four times at 40 minute intervals; the first two as active enzymes and subsequently as heat denatured proportions. Secretin was continuously infused intravenously (0.5 E/kg bw/h) to achieve minimal pancreatic flow. Lipase, amylase, trypsin, chymotrypsin, volume, and bicarbonate were measured in duodenal contents in eight pooled 15 minute fractions. Three subjects who received HEPES-Ringer buffer instead of pancreatic enzymes served as controls. Plasma cholecystokinin (CCK) was measured using a sensitive bioassay. Both active and heat denatured pancreatic extracts caused a small but significant increase in amylase and chymotrypsin secretion. Basal plasma CCK values were 0.85 (0.05) pM. After intrajejunal instillation of either active or heat denatured pancreatic extracts plasma CCK rose to 3.25 (0.30) pM and to 3.28 (0.36) pM respectively. In a second group of five volunteers, plasma CCK concentrations were measured after a test meal. On day 1, volunteers received a liquid fat and protein rich meal and on day 2, the same test meal containing porcine pancreatic extracts. In both cases, a similar increase in plasma CCK was observed. We conclude that therapy with pancreatic extracts stimulate pancreatic enzyme secretion. This may be mediated through release of CCK.
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PMID:Influence of treatment with pancreatic extracts on pancreatic enzyme secretion. 231 90

Pancreozymin-secretin tests were carried out in children aged from 0,5 till 12 years by means of a two lumen tube of the Salem-Sump-type and a three lumen perfusion tube. For stimulation we used 2 U/kg of the hormones, each from BOOTs-Corp. Amylase was determined with dinitrosalicylic acid, lipase by titration of acidic equivalents after half hour incubation and trypsin and chymotrypsin with TAME and BTEE respectively. We used PEG 4000 as marker and quantified enzymes secretion as well as liquid secretion by it. We got up to 50% lower results by testing with the two lumen tube. If we are laying the perfusion tube we measured an elevation of the two lumen tube. If we are laying the perfusion tube we measured an elevation of the II-hydroxycorticoides. The concentration of the enzymes in the specimines before perfusion on 3 consecutive days fell by 90% on the average. We discussed some problems of the determination of enzymes and performing of the tests by means of the results.
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PMID:[Problems in the determination of pancreatic enzymes for the quantitative functional diagnosis of the pancreas in children]. 616 43

A fraction increasing water and sodium absorption in rat duodenum was detected in the material obtained at an early stage of purification of the hitherto isolated duodenal hormones. In Wistar rats, duodenal loops were made in situ and filled with a solution containing 0.138 mM NaCl, with 14C PEG and 22Na as markers; the final content was collected after 1 h and the movements of water and Na measured. In contrast to secretin, cholecystokinin, and somatostatin, which induced duodenal secretion, and with pentagastrin, which induced duodenal absorption and stimulated acid secretion, this fraction induced duodenal absorption f Na and water without stimulating acid secretion. The fraction was obtained by chromatography of a concentrate of intestinal peptides in 0.2 M acetic acid on Sephadex G25 (fine), and its active component was found to be methanol-soluble at pH4 and insoluble at pH7.5. It was eluted from carboxymethylcellulose 22 with 0.04 M ammonium bicarbonate and gel filtration of Sephadex G50 *fine), resulting in a tenfold increase in activity. Incubation with chymotrypsin suppressed the biological activity, indicating a peptidic nature. The substance displayed biological and radioimmunological properties distinct from those of the gastrointestinal hormones. Particularly, no cross-reactivity was found with gastrin, prolactin, and angiotensin, which are known to increase intestinal absorption. It therefore seems possible that the activity described is due to a peptide that has as yet not been isolated. The name 'sorbin' is proposed for this active principle.
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PMID:Sorbin, a peptide contained in porcine upper small intestine which induces the absorption of water and sodium in the rat duodenum. 679 42

1. alpha 2-Macroglobulin (alpha 2M) activity is present in the serum of the ostrich, Struthio camelus. The chromogenic synthetic peptide substrates BAPNA and ATNA were hydrolysed by trypsin and chymotrypsin, respectively, in the presence of ostrich serum and the alpha 2 M in ostrich serum protected trypsin from being inhibited by soybean trypsin inhibitor. Ostrich alpha 2M proved to be a potent inhibitor of bovine pancreatic trypsin and chymotrypsin. 2. alpha 2M was purified to apparent homogeneity by PEG precipitation, DEAE-Toyopearl 650M, Bio-Gel A-5m and Zn(2+)-affinity chromatography. 3. Ostrich alpha 2M migrated as a single band (M(r) 779,000 during non-denaturing gradient gel electrophoresis and showed increased mobility after reaction with trypsin. Denaturation dissociated ostrich alpha 2M into half-molecules. Denaturation with reduction further dissociated the protein into quarter-subunits. 4. Isoelectric focusing revealed a pI of 5.3. 5. The amino acid composition of ostrich alpha 2M is typical of an alpha 2M, comparing favourably with those of other animal species. The carbohydrate composition of the purified protein, in percentage dry weight of the molecule, was galactose: mannose (1:1), 4.55; N-acetylglucosamine 2.35; N-acetylneuraminic acid, 0.58; and fucose, 0.77. 6. alpha 2M was assessed immunologically by Ouchterlony double-diffusion and Western blot analysis with polyvalent antisera directed against ostrich alpha 2M. 7. Ostrich alpha 2M seems to show many physical, chemical and kinetic properties similar to those of other known alpha 2M(s), but is expected to differ from other alpha Ms when considering the primary structure of the bait region, the area differing among alpha Ms from different species and determining its specificity.
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PMID:The isolation and partial characterization of alpha 2-macroglobulin from the serum of the ostrich (Struthio camelus. 751 Nov 19

The Bowman-Birk family of proteinase inhibitors from seeds of leguminous plants usually have a molecular mass of 8000 to 10,000 Da. Horse gram (Dolichos bifloros or Macrotyloma uniflorum) seeds contain an unusual Bowman-Birk inhibitor of molecular mass 15,500 Da active against both trypsin and chymotrypsin. In order to elucidate its three-dimensional structure, its evolutionary relationship with the more usual Bowman-Birk inhibitors and to study the structure-function properties, this inhibitor has been purified and crystallized. The purified protein crystallizes easily under a variety of conditions in different crystal forms. Crystals obtained by precipitating the protein (3 to 5 mg/ml in 50mM Tris.HCl (pH 8.0)) with 5% ammonium sulphate and 2 to 3% PEG 4000 appear to be suitable for structure determination by X-ray diffraction. The crystals belong to cubic space group P2(1)3 (a = 110.81 A) and diffract X-rays to beyond 3.0 A resolution.
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PMID:Crystallization and preliminary X-ray diffraction studies on a trypsin/chymotrypsin double-headed inhibitor from horse gram. 828 58

Conjugates of alpha-chymotrypsin (ChT) with poly(ethylene glycol) (PEG) and block copolymers of ethylene oxide and propylene oxide (proxanols) have been synthesized. The molecular mass of the polymers was 2 kDa. The conjugates contained 5 to 7 polymeric chains per enzyme molecule. Hydrolysis of N-trans-cinnamoylimidazole catalyzed by conjugates of ChT with poly(alkylene oxides) was studied in 0.05 M Tris-HCl buffer, pH 8.0, and in hydrated reversed micelles of aerosol OT (AOT) in octane at 25 degrees C. The deacylation constant, k3, for the conjugates in the buffer solution was found to be 1.5-1.8-fold higher than the corresponding value for native ChT. The value of the [H2O]/[AOT] ratio corresponding to the maximum on the k3 versus [H2O]/[AOT] curves for the conjugates (around 16) allows the dimensions of their molecules to be characterized. The radius of the conjugate molecules was found to be approximately equal to 2.8 nm. The k3 value for the conjugate of ChT with PEG, as in the case of native ChT, remains constant when the concentration of AOT is varied. However, the deacylation constant for ChT conjugates with proxanols decreases with a rise in AOT concentration. This fact indicates that ChT conjugates with proxanols are able to interact with the micellar matrix, i.e., they possess membranotropic properties.
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PMID:[Conjugates of alpha-chymotrypsin with polyalkylene oxides in hydrated reverse micelles]. 867 74


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