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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

All human, simian, bovine and avian adenovirus types tested so far and the canine hepatitis virus induce interferon production in chick cells. This finding indicated this property to be characteristic for viruses belonging to the adenovirus group. Trypsin treatment, which had no effect upon the infectivity, diminished or eliminated the interferon-inducing abilities of crude adenoviruses, and thus the need for a trypsin-sensitive protein in interferon induction was suggested. T antigen and interferon were formed simultaneously in chick embryo fibroblast cells infected with human adenovirus type 12, and therefore the adenovirus-specific T antigen was resistant to the action of endogenous interferon synthetized by the same cells. In chicks inoculated with human types, the appearance of interferon was biphasic: an 'early' and a 'late' interferon could be demonstrated with maximum titre 4 and 10 hr, respectively, after virus infection. In chicks infected with adenoviruses, first interferon production and then a decreased primary immune response to sheep red blood cells was observed. It was assumed that in adenovirus-infected chicks the interferon produced by viral stimulus resulted in a transient immunosuppression.
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PMID:Interferon induction by adenoviruses. 22 39

The infectivity of a bovine rotavirus was enhanced 140-, 8-, and 3-fold, respectively, by trypsin, protease, and lactase. Ficin, carboxypeptidases A and B, lysozyme, and beta-galactosidase had little effect on the infectivity. Chymotrypsin caused a threefold decrease in the infectivity. Trypsin acts directly on the rotavirus and not on the host cell.
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PMID:Effect of enzymes on rotavirus infectivity. 22 17

Cells growing on plastic or glass surfaces in vitro may be brought into suspension by proteases (e.g. trypsin) or chelating agents (e.g. EGTA). Trypsin and EGTA remove different quantities and types of molecules from cell surfaces. Previous studies have revealed that when confluent cultures of either BHK or PyBHK cells are brought into suspension by exposure to trypsin, foetal calf serum (or fibronectin) is required for cell attachment to films of denature type I collagen, but not to 3-dimensional gels of native collagen fibres. In this communication the serum requirements for the attachment of BHK and PyBHK cells to collagen substrata have been examined as a function of (a) the method used to prepare the cell suspension (EGTA or trypsin), and (b) cell density. Data are presented consistent with the view that cell surface-associated fibronectin is able to mediate cell attachment directly to films of denatured collagen.
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PMID:The effects of EGTA and trypsin on the serum requirements for cell attachment to collagens. 23 8

Tertiary amine local anesthetics cause a time- and dose-dependent, reversible increase in insulin binding sites in cultured chick embryo fibroblasts. Incubation of fibroblasts with 0.2 mM dibucaine for 3 h at 37 degrees C results in a twofold to threefold increase in insulin binding, with an increase in average number of binding sites (Ka = 3.0 X 10(7) M-1) from 9 X 10(3) per cell. Trypsin or ethyleneglycoltetraacetic acid (EGTA) alone increases insulin binding twofold to threefold, but fails to further increase 125I-insulin binding in cells pretreated with dibucaine. Transformation of chick embryo fibroblasts with Rous sarcoma virus causes a threefold to fivefold increase in insulin binding, which is not further increased by incubation with dibucaine. As demonstrated by transmission electron microscopy, dibucaine and trypsin also induce changes in the cytoskeleton of chick embryo fibroblasts, characterized by disorganization and disappearance of microfilament and microtubule bundles. These alterations are accompanied by gross morphologic changes, including rounding of cells and appearance of numerous ruffles and blebs on the cell surface. These observations are consistent with the hypothesis that expression of surface receptors in cultured chick embryo fibroblasts is related to the organization and disorganization of cytoskeletal structures.
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PMID:Alteration of insulin binding and cytoskeletal organization in cultured fibroblasts by tertiary amine local anesthetics. 23 24

The esterolytic activity of mixed and parotid saliva in cystic fibrosis (CF) patients and normal subjects was determined using BAEE (alpha-Benzoyl-1-arginine-ethylester) as the substrate. Using soybean-trypsin-inhibitor the trypsin-like activity (TLA) was measured and plotted as a function of parotid flow rate. In addition calcium, protein and pH were determined. Trypsin-like activity in mixed and parotid saliva showed large individual variations in CF and normal children. In parotid saliva we could not find any significant difference, whereas a reduction of TLA in mixed saliva of CF patients was observed. The fact that our normal values fell within the range of heterozygotes reported by Rao et al. (19), makes their hypothesis of a close relationship between reduced TLA and the genetic defect very doubtful. Protein, calcium and pH increased with augmented salivation and no difference between CF patients and normal age matched children could be found except for the pH at a flow rate above 0.75 ml/min per m2 body surface where significantly lower pH values resulted. The relevance of reduced TLA to the pathogenesis of cystic fibrosis is discussed.
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PMID:Excretion of trypsin-like activity, electrolytes and protein in mixed and parotid saliva of patients with cystic fibrosis of the pancreas. 23 50

The reoxidation of fully reduced and denatured bovine trypsinogen and the regeneration of the native structure can be accomplished if the protein is initially attached to Agarose beads. Reoxidation was performed under aerobic conditions, in the presence of mercaptoethanol and dehydroascorbate or with a mixture of reduced and oxidized glutathione. In 24 hours, the yields of regenerated trypsinogen were 60 to 70% with 0.2 to 0.6 mg of protein bound/ml of gel but 30% or less if greater than 1.7 mg of protein were bound. Rapid reoxidation, with dehydroascorbate as catalyst, gave molecules which could not be converted to active trypsin. However, if the incorrectly folded structures were placed in a mixture of reduced and oxidized glutathione, the molecules underwent disulfide interchange and could continue to refold. The rapidly reoxidized molecules regained their native structure with the same rate and to the same extent as they did initially in the absence of rapid reoxidation. Therefore, the rate-limiting step in the refolding of trypsinogen was disulfide interchange. The regenerated Agarose-bound trypsinogen displayed the usual properties of the native molecule in (a) its conversion to active trypsin by a process of limited proteolysis, (b) the kinetic constants of the activated product toward typical trypsin substrates, and (c) the limited cleavage of 1 disulfide bond with sodium borohydride. Refoldind of immobilized trypsin was also observed with an overall yield of 50%. Trypsin can fold spontaneously to its native structure even though it lacks the NH2-terminal hexapeptide of its precursor.
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PMID:Refolding of reduced, denatured trypsinogen and trypsin immobilized on Agarose beads. 24 50

Effects of trypsin and pronase on D-xylose uptake were studied on isolated frog sartorius muscle. Trypsin and pronase exerted insulin-like effects on the transport of sugar. The acceleration of xylose transport by insulin was reduced by a prior incubation of muscles with trypsin or pronase. The inhibition of insulin effect was not due to destruction of the hormone. Proteases had no effect upon the sugar transport stimulated by DNP or potassium contracture. A conclusion is made of the availability in the frog muscle membrane of some insulin receptor similar to that reported for muscle tissue and fat cells of mammals.
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PMID:[Effect of proteases on sugar transport in muscle tissue]. 30 25

The distribution of trypsin between the protease inhibitors of human serum with and without Trasylol was studied in vitro. 1) Trypsin was preferentially bound by alpha2-macroglobulin on addition of small amounts of the enzyme to normal serum in both the presence and absence of Trasylol in a molar concentration equal to that of alpha2-macroglobulin. 2) On saturation of alpha2-macroglobulin, a considerable amount of trypsin was bound by Trasylol even when most of the serum alpha1-antitrypsin was in a free form. 3) In reaction mixtures containing small amounts of trypsin, Trasylol was identified in a free form as well as in complex with trypsin-alpha2-macroglobulin complex and to a limited extent with trypsin. 4) With larger amounts of trypsin, sufficient to saturate alpha2-macroglobulin, increasing amounts of Trasylol were bound to trypsin. The relative amount of Trasylol bound to trypsin-alpha2-macroglobulin complexes was now smaller. This was explained by a higher affinity (or binding rate) of Trasylol for trypsin than for trypsin-alpha2-macroglobulin complexes. 5) Trypsin-Trasylol complexes showed no signs of dissociation after 5 h incubation at 37 degrees C in serum.
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PMID:Studies on the influence of Trasylol on the partition of trypsin between the human plasma protease inhibitors in vitro. 30 26

The mechanism of the increase in renin activity in human plasma which had been kept -5 degrees C for 4 days (cryoactivation) was investigated. From the results of clinical studies, it is likely that the controling mechanism of inactive renin has something in common with that of active renin. The experimental data showed that the increase in renin activity of human plasma by cryoactivation was closely correlated to the increase obtained by incubation with trypsin (r = 0.88, p less than 0.001, n = 10). Soybean trypsin inhibitor, aprotinin and di-isopropylfluorophosphate (DFP) inhibited cryoactivation, indicating that the cryoactivation is due to the action of a trypsin-like serine enzyme. Trypsin which had no effect on plasma renin activity in the presence of the same amount of soybean trypsin inhibitor at 37 degrees C, activated the renin activity during cold incubation, suggesting that the dissociation of the trypsin-inhibitor complex may have taken place at a low temperature. Endogenous trypsin inhibitor is also likely to lose its affinity to endogenous trypsin-like enzyme at a low temperature.
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PMID:Cryoactivation of inactive renin in human plasma. 31 80

1. All the porcine pancreas enzymes tested, regardless of their pI's were adsorbed on Amberlite CG-50 (a weakly acidic cation exchange resin) at pH 4, where the ion-exchange group (carboxyl group) is not dissociated. The adsorption is hardly influenced by ionic strength. 2. At pH 4, the adsorbed enzymes were partially eluted by organic solvents such as 50% propanol. 3. The adsorbed enzymes were effectively eluted by increasing the pH from 4 to 6. Trypsin (pI 10.5) was eluted before carboxypeptidase A (pI 4.5 AND 5.3) WITH 0.5 M acetate buffer, whereas the former enzyme was eluted after the latter enzyme with 0.2 M 3,3-dimethyl glutarate buffer. However, with either buffer, the elution order of enzymes was not always the same as the order of the pI's. 4. By a single Amberlite CG-50 column chromatography of porcine pancreas extracts, kallikrein, carboxypeptidase B, deoxyribonuclease, carboxypeptidase A, and trypsin were purified 100-fold, 16-fmately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 cellulose column chromatography, gel filtration on Sephadex G-100, preparative polyacrylamide gel electrophoresis, and affinity chromatography on 5' AMP-Sepharose 4B. The last procedure, affinity chromatography on 5' AMP-Sepharose 4B, was useful for the removal of other dehydrogenases. The enzyme which was homogeneous, as shown by polyacrylamide gel electrophoresis, had a molecular weight of about 92,000. The optimum pH was at 10.0 and isoelectric point at 5.2. The enzyme accepted both L-fucose and D-arabinose as substrate, but was specific for NAD+ as coenzyme. Km values were 0.15 mM, 1.4 mM, and 0.07 mM for L-fucose, D-arabinose, and NAD+, respectively. A single enzyme catalyzed the oxidation of L-fucose and D-arabinose, which had the same configurations of hydroxyl groups from C-2 to C-4. The reaction products obtained with L-fucose as substrate were L-fucono-lactone and L-fuconic acid. The L-fucono-lactone was an immediate product of oxidation and was hydrolyzed to L-fuconic acid spontaneously. This reaction was irreversible. Therefore, it is likely that L-fucose dehydrogenase is involved in the initial step of the catabolic pathway of L-fucose in rabbit liver.
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PMID:Hydrophobic-ionic chromatography. Its application to purification of porcine pancreas enzymes. 31 32


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