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)

This study was undertaken to determine the involvement of endogenous cholecystokinin (CCK) in the regeneration of pancreatic tissue after cerulein-induced acute pancreatitis treated by the CCK receptor antagonist L364,718. Acute pancreatitis was induced in rats by s.c. injections of cerulein in gelatin (12 micrograms/kg) three times a day for 2 days with controls receiving saline in gelatin. Rats were then divided into four treatment groups: saline-dimethyl sulfoxide (DMSO) (SD), saline-L364,718 (SA), cerulein-pancreatitis-DMSO (CD), and cerulein-pancreatitis-L364,718 (CA). In the first experiment, rats were treated for 3 or 10 days with DMSO or L364,718 (0.1 mg/kg, twice a day). In the second experiment, rats were treated for 13 days with DMSO or L364,718 (1.0 mg/kg, twice a day). After the rats were killed, pancreata were weighed and evaluated for their total protein, amylase, chymotrypsin, RNA, and DNA. We found that destruction of the pancreatic tissue occurred after cerulein-induced pancreatitis and that regeneration of the tissue was in progress but incomplete after 10 days; the low dose of L364,718 did not prevent regeneration. After 13 days, regeneration was still incomplete but the 1-mg dose of L364,718 strongly inhibited spontaneous regeneration. These data suggest that endogenous CCK is an important and potent trophic factor in the regeneration process of pancreatic tissue following an episode of acute pancreatitis.
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PMID:Involvement of endogenous cholecystokinin in pancreatic regeneration after cerulein-induced acute pancreatitis. 159 50

This study was an investigation of the role of cholecystokinin (CCK) in the stimulatory action of cholestyramine on rat exocrine pancreas. Postprandial CCK release was significantly enhanced by acute administration of cholestyramine (12.7 +/- 1.8 vs 3.7 +/- 0.5 pmol/L in controls). Over four weeks, rats were fed either regular diet or diet containing 6% cholestyramine, and were treated with the specific CCK receptor antagonist L-364,718 (2 x 0.5 mg/kg body weight/day s.c.) or DMSO (vehicle for the antagonist). Cholestyramine significantly increased pancreatic weight and trypsin and chymotrypsin contents. L-364,718 abolished these effects. Concomitant administration of antagonist and cholestyramine elevated amylase content, compared to controls. CCK levels in fasted animals did not differ between the four groups. The effect of the same dose of L-364,718 on pancreatic enzyme depletion, induced by the protease inhibitor camostate, was studied in a control experiment. A single dose of camostate (200 mg/kg) caused a 44-68% decrease in enzyme content. L-364,718 reversed this effect for all enzymes. We conclude that CCK is the mediator of cholestyramine-induced pancreatic hypertrophy and increase in content of proteases. After long-term administration, the CCK receptor antagonist, in combination with cholestyramine revealed an agonistic effect on individual, pancreatic enzyme content.
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PMID:Role of cholecystokinin in cholestyramine-induced changes of the exocrine pancreas. 194 14

Mouse oocytes, with or without an intact cumulus mass, were exposed to various concentrations of dimethyl sulfoxide (DMSO) at different temperatures for different periods of time and using different protocols of DMSO addition and removal. The effect of these procedures on the chymotrypsin sensitivity of the zona pellucida and the fertilizability of the oocytes was then assessed. Some procedures were found to affect adversely both the zona pellucida and the cumulus mass, resulting in reductions in the fertilization rate. As a result of both these and previously reported experiments (1-3), an optimal schedule is proposed for the handling of mouse oocytes during cryopreservation, namely, to equilibrate cumulus-intact oocytes in 1.5 M DMSO precooled to 4 degrees C prior to freezing, to remove DMSO at 4 degrees C after thawing prior to restoring the oocytes to 37 degrees C, to loosen or remove the cumulus cells, and then to hold oocytes at 37 degrees C for at least 1 hr to allow recovery of the spindle prior to insemination.
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PMID:The effect on fertilization of exposure of mouse oocytes to dimethyl sulfoxide: an optimal protocol. 267 90

Human promyelocytic cells (HL-60) were labeled with 35S-sulfate and either 3H-glucosamine or 3H-serine as precursors. Accumulation of 35S-labeled macromolecules was approximately linear for up to 96 h, with a mean cell:medium ratio of 5.5:1, although activity/10(5) viable cells reached a plateau level after 24 h. Virtually none of the cell-associated proteoglycan was removed by trypsinization, consistent with a predominantly intracellular localization. Proteoglycan heterogeneity was investigated by DEAE-Sephacel chromatography, isopyknic CsCl gradient centrifugation, and gel filtration chromatography. HL-60 cells appeared to synthesize a single proteoglycan species, Kav = 0.46 on Sepharose CL-4B and Kav = 0.32 on Sepharose CL-6B, recovered primarily from the high-density fractions of a dissociative CsCl gradient (rho greater than 1.40 g/l). Degradation products of lower charge density, lower buoyant density, and lower hydrodynamic size were also present, mainly in the cell pellets. The major proteoglycan was found to contain chondroitin sulfate chains of average Mr = 14.5 kD, yielding virtually 100% 4-sulfated disaccharides on digestion with chondroitinase ABC. The proteoglycan was resistant to trypsin, chymotrypsin, plasmin, and papain, and the core protein Mr was approximately 20 kD by molecular sieve chromatography. Induction of HL-60 cells with 0.15 dimethyl sulfoxide (DMSO) resulted in differentiation to a more mature granulocytic phenotype and was associated with a reduction in 35S-sulfate incorporation to 45% of control values or 32%, expressed as activity/10(5) cells. Proteoglycans synthesized by DMSO-treated cells were identical to those from untreated cells in terms of hydrodynamic size, glycosaminoglycan Mr, and sulfation.
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PMID:Biosynthesis of proteochondroitin sulfate by HL-60 human promyelocytic cells. 291 Oct 20

Cytochalasin B has been reported to inhibit fibrinogen binding and aggregation of rabbit platelets in response to ADP. The present study was designed to ascertain whether cytochalasins B and D inhibit aggregation by interfering with the exposure of fibrinogen receptors or more directly by inhibiting binding to available receptors. Aspirin-treated, washed, human platelets stimulated with ADP or chymotrypsin were used for these studies. Neither cytochalasin B nor D significantly inhibited the binding of fibrinogen to chymotrypsin-treated platelets when these agents were added to platelet suspensions before (16 +/- 8% (mean +/- SD) inhibition, N = 8), or after (15 +/- 10% inhibition, N = 13) chymotrypsin treatment, i.e., before or after fibrinogen receptor exposure. This apparent lack of cytoskeletal involvement was consistent with the observation that chymotrypsin-treated platelets were unable to retract reptilase-induced fibrin clots, an activity that was restored by adding ADP. In contrast, incubating platelets with either cytochalasin B or D for 30 min before or after stimulation with ADP decreased fibrinogen binding by 42 +/- 16% (N = 13) and 27 +/- 11% (N = 8), respectively, compared to DMSO-treated controls. Platelets stimulated with ADP and incubated with DMSO for 30 min, however, became refractory and aggregated poorly in response to a second dose of ADP. In comparison, platelets stimulated with ADP, but incubated with cytochalasin B or D, aggregated more extensively when stimulated by a second dose of ADP despite diminished fibrinogen binding. The data suggest (1) microfilament polymerization is important not only for the exposure of fibrinogen receptors by ADP, but also for preserving the ability of exposed receptors to bind fibrinogen, (2) exposure of fibrinogen receptors by chymotrypsin is not accompanied by significant cytoskeletal activation, and (3) cytochalasins may impart partial protective effects against the development of ADP-induced refractoriness.
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PMID:Observations on the effects of cytochalasin B and cytochalasin D on ADP- and chymotrypsin-treated platelets. 669 66

The major integral membrane protein of red blood cells, the mouse equivalent of human band 3, was purified and used to raise a specfic antiserum. The murine protein resembles its human counterpart in several of its properties, including susceptibility to digestion by chymotrypsin added to intact cells and an ability to bind to concanavalin A. The synthesis of 35S-labeled band 3 was detected in Friend erythroleukemia cells treated with DMSO by immuneprecipitation followed by SDS gel electrophoresis and fluorography. Induction with DMSO led to a greater than tenfold increase in the synthesis of band 3 and maximal synthesis was reached 3 to 4 days after the beginning of induction.
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PMID:Biosynthesis of erythrocyte membrane protein band 3 in DMSO-induced Friend erythroleukemia cells. 693 32

A nonapeptide Ac-His-Phe-Gly-Cys-D-Phe-Ser-Gly-Glu-Cys-NH2 (XI) cyclized through the cysteines at positions 4 and 9 is synthesized as a model active site for the enzyme alpha-chymotrypsin. A CPK model of XI indicates that the peptide will have a high probability of folding into a conformation in which the two beta-phenyls interact to form a hydrophobic site to one side of the cyclohexyl structure, and the Ser-His-Glu side chains form a hydrogen bonded triad over the plane of cyclopeptidyl structure. Substrates can then bind at the hydrophobic pocket formed by the beta-phenyls and be acted upon by the Ser-His-Glu catalytic triad, as in the enzyme. 1H. n.m.r. shows: (i) multiplet peaks for the phenyl protons in D2O that condense to a singlet in DMSO-d6, (ii) a perturbation of the phenyl protons chemical shift on proflavin association to XI, and (iii) perturbation of the His pKa to a higher value on association of proflavin to XI. These data support the existence of a hydrophobic site and a Glu-His interaction in the peptide. Furthermore, the greater than 10(2) better affinity of proflavin to XI than to AcTrp supports the existence of a hydrophobic site. However, no acceleration of p-nitrophenyl acetate or trans-cinnamoyl imidazole hydrolysis over that of imidazole is observed. The possible reasons for a lack of esterase activity in XI and other peptidyl models of serine protease active sites are discussed.
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PMID:Synthesis and conformational properties of a synthetic cyclic peptide for the active site of alpha-chymotrypsin. 711 15

The alpha-chymotrypsin (EC 3.4.21.1)-catalyzed reaction of Mal-Phe-OMe with H-Leu-NH2 has been studied under a range of reaction conditions, for example various cryogenic reagents for shock-freezing, addition of dimethyl sulfoxide (DMSO) and decreased reaction temperatures down to 213 K. It has been shown that the peptide yield is independent of the method of shock-freezing. The optimal reaction temperature was between 263 K and 248 K. Lower temperatures result in clearly retarded reactions. Addition of DMSO leads to decreasing peptide yields. It is certain that the peptide bond formation is catalyzed by the active enzyme, since unspecific protein surface catalysis gave no peptide yields at all.
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PMID:Enzymatic peptide synthesis in frozen aqueous systems: influence of modified reaction conditions on the peptide yield. 771 Jun 98

Mouse oocyte-cumulus masses were added to 1.5 dimethyl sulphoxide (DMSO) + 20% fetal bovine serum (FBS) that had been precooled at +4 degrees C, were frozen by slow cooling to an intermediate temperature of -60 degrees C before being plunged into liquid nitrogen at -196 degrees C, subjected to a controlled thaw, expelled into 1.5 M DMSO + FBS at 4 degrees C, and then washed in medium + FBS at 37 degrees C. Of 7733 oocytes treated, 78.4% were viable (controls; no treatment: 94.2% of 2764 oocytes; cryoprotectant only: 92.2% of 2991 oocytes). The oocyte losses were not due to complete loss of all oocytes from some straws or mice, since analysis of individual straws containing oocytes from a single mouse revealed considerable inter-straw/mouse variation. Amongst surviving oocytes, no significant differences between frozen and control oocytes in spindle, chromosomal or microfilament organization were recorded. Two significant differences were observed: (i) fewer frozen-thawed oocytes had zonae resistant to chymotrypsin digestion, and (ii) spindle organization in control oocytes, but not frozen-thawed oocytes, was improved by 3 h incubation at 37 degrees C. More of the abnormal than the normal frozen-thawed and control oocytes were surrounded by zonae which were resistant to digestion by chymotrypsin.
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PMID:Cytoskeletal organization and zona sensitivity to digestion by chymotrypsin of frozen-thawed mouse oocytes. 825 47

Two ways for semi-enzymatic preparation of the peptide aldehydes are proposed: (1) enzymatic acylation of amino alcohols with acyl peptide esters and subsequent chemical oxidation of the resulting peptide alcohols with DMSO/acetic anhydride mixture or (2) enzymatic acylation of the preliminarily obtained by a chemical route amino aldehyde semicarbazones. Subtilisin 72, serine proteinase with a broad specificity, distributed over macroporous silica, was used as a catalyst in both cases. Due to the practical absence of water in the reaction mixtures the yields of the products in both enzymatic reactions were nearly quantitative. The second way seems to be more attractive because all chemical stages were carried out with amino acid derivatives, far less valuable compounds than peptide ones. A series of peptide aldehydes of general formula Z-Ala-Ala-Xaa-al (where Xaa-al = leucinal, phenylalaninal, alaninal, valinal) was obtained. The inhibition parameters for these compounds, in the hydrolysis reactions of corresponding chromogenic substrates for subtilisin and alpha-chymotrypsin, were determined.
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PMID:Synthesis of peptide aldehydes via enzymatic acylation of amino aldehyde derivatives. 1065 1


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