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)

An easily performed assay to identify the C3b and Fc receptors on human neutrophils was developed. Salmonella typhimurium were treated with fluorescein and then incubated in nonimmune fresh human serum, which led to C3b fixation via activation of the alternative pathway. Similarly, type II pneumococci were treated with fluorescein and opsonized with type-specific rabbit antiserum. Neutrophils bearing C3b and Fc receptors formed rosettes with the respective bacteria, which were easily readable because of their bright fluorescence. Incubation of neutrophils at 37 degrees C with C3-coated bacteria generated 54 +/ 4% C3b rosettes, whereas neutrophils incubated with immunoglobulin G-coated bacteria yielded 75 +/ 7% rosettes. Incubation at 4 degrees C inhibited the formation of C3b rosettes but not Fc rosettes. Heat inactivation of the fresh human serum at 56 degrees C for 30 min completely inhibited the formation of the C3b rosettes, and addition of heat-aggregated immunoglobulin G to the polymorphonuclear leukocyte blocked the ability of the polymorphonuclear leukocyte to bind immunoglobulin G-coated bacteria. Addition of 1.0 mM N-ethylmaleimide, 0.1 mg of trypsin per ml, 10 mM H2O2, O2- generated by xanthine-xanthine oxidase, and 8 times 10(-4) M hydrocortisone inhibited the C3b receptor, but did not inhibit the Fc receptor. In neutrophils, the selective effect of the various inhibitors suggests that the Fc and C3b receptors are distinct entities.
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PMID:Effects of surface-active agents on neutrophil receptors. 3 Jun 96

Some proteases, i.e. trypsin, alpha-chymotrypsin, thermolysin, proteinase K, alpha-amylase, collagenase, and papain were investigated on their effect on isolated zonular fibers. All these enzymes but collagenase were zonulolytic active. An attack on the ground substance of the fibers by substances solving glycosaminoglycans and proteoglycans (hyaluronidase, EDTA, guanidinium chloride, H2O2) showed an increased effect of the enzymes used. These results suggest that the interfibrillar matrix has a protective function on the zonular fibers.
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PMID:[The attack of different proteases on isolated zonular fibers (author's transl)]. 13 75

We have developed assays for thyroid peroxidase in crude thyroid tissue preparations, in which a linear relationship between activity and amount of tissue could be demonstrated. Linear assays were developed based on the following peroxidase catalyzed reactions in the presence of H2O2:(1) oxidation of I- to I(-3), (2) oxidation of guaiacol, and (3) iodination of human goiter thyroglobulin. To attain satisfactory linearity we found it necessary to solubilize the enzyme beforehand. This was accomplished by a brief treatment of the particulate fraction with trypsin and deoxycholate, followed by centrifugation at 40 000 X g and dialysis. Not only did this treatment facilitate the development of linear assays, but it also resulted in a substantial increase in enzyme activity compared with that in the untreated particulate fraction. The use of a Polytron homogenizer for the initial disruption of the tissue also proved helpful in developing these assay procedures. The three different assays were used to measure peroxidase activities in human thyroid adenomas and in normal tissue derived from adenomatous glands. T he adenomas generally displayed a higher level of peroxidase activity than normal tissue. The greatest difference was observed with the iodination assay and the smallest difference with the guaiacol assay.
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PMID:Improved assay procedures for thyroid peroxidase; application to normal and adenomatous human thyroid tissue. 62 Apr 58

The bovine pancreatic inhibitor of trypsin (trasylol, Bayer) (T) and the soy bean trypsin inhibitor (SBI) were coupled with peroxidase (P). With each one of these coupling products (T and P and SBI and P) the cell distribution of proteolytic enzymes (PE) of ascitic cells of L5178Y murine lymphoma, was localized. The reactions were developed by means of Karnowsky's reaction with diaminobenzidine and H2O2. The preparations were observed under light and electronic microscopy. It was found that L5178Y cells contain intracellular PE in granules measuring 0.1 to 0.8 min diameter, and superficial PE that form a continuous layer of 80 to 120 nm over the cell surface. Superficial PE were not identified in 20 per cent of L5178Y cells, while in every case intracellular granules were found. Both the macrophages and the polimorphonuclear cells present in the ascitic fluid contained intracellular PE granules measuring 0.05 to 0.4 micron in diameter, and did not contain superficial PE.
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PMID:Proteolytic enzymes marking of malignant lymphoblasts, study of the L5178Y murine lymphoma. 63 54

Porcine thyroid peroxidase (Iodide: hydrogen-peroxide oxidoreductase, EC 1.11.1.8) was solubilized by proteolytic and non-proteolytic procedures. A kinetic and physical study was undertaken to ascertain the catalytic properties of the peroxidase prepared by the two purported solubilization procedures. Where possible, the properties of the two enzyme preparations were compared with the original microsomal preparation. The n-butanol-solubilized thyroid iodide peroxidase is not truly soluble, but exists as a large molecular weight lipoprotein aggregate. The trypsin-solubilized thyroid iodide peroxidase is truly soluble, active, and contains lipids. The microsomes, butanol-pseudosolubilized enzyme, and trypsin-solubilized enzyme have similar kinetic properties such as pH optima, Km for iodide and H2O2, sigmoid character of the saturation curves, substrate inhibition, and inhibition by 3,5-diiodotyrosine. Since the proteolytic solubilization procedure produced a soluble peroxidase with catalytic properties similar to the microsomal preparation, trypsin-solubilized peroxidase can be studied with reasonable assurance that its properties are essentially unaltered and are not artifacts of the solubilization procedure.
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PMID:The characterization of n-butanol-pseudosolubilized and trypsin-solubilized porcine thyroid iodide peroxidase. 71 42

A topographical study of the articular surface of 21 femoral heads removed for surgery of osteoarthrosis was made using the scanning electron microscope. Sections of degenerate cartilage were pretreated with H2O2 and trypsin to reveal the collagenous framework. Torn and frayed collagen bundles were evident on all the specimens studied, the length of these bundles varying from 20 to 150 micron. The frequency of the bundles over the degenerate fibrous areas varied considerably, and bundle sizes ranged from 20 to 70 micron. The topography of a single femoral head removed from a rheumatoid arthritic was very much smoother, with torn fibre ends ruptured at the same level. Although the exposed bone was considerably "smoother" than the residual fibrocartilage, ruptured osteons and trabeculae revealed large voids in the surface which would presumably alter the lubrication and fluid flow characteristics of the functioning joint. The effects of these changes on joint tension and lubrication are discussed.
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PMID:Osteoarthrotic articular cartilage lesions of the femoral head observed in the scanning electron microscope. 87 41

Three methionine-modified derivatives of ovine prolactin have been prepared: two by oxidation of the methionines by H2O2 to sulfoxide (partial and complete), and the third by complete alkylation of the metionines with iodoacetic acid to the carboxymethyl sulfonium salts. The derivatives were characterized by exclusion chromatography, amino acid composition, circular dichroism spectra, relative rates of digestion by trypsin, and biological activity. Partially oxidized prolactin, having four of its seven methionines oxidized, was very similar to the native hormone. The unmodified methionines in partially oxidized prolactin were found to be the residues at positions 36, 81 and 132. The prolactin derivatives in which all the methionines had been oxidized, or alkylated, showed major changes in all parameters examined. In addition, circular dichroism spectra indicated that complete modification of all the methionines in prolactin exposes the normally buried tryptophans.
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PMID:Studies on pituitary prolactin. 39. Reaction of the ovine hormone with hydrogen peroxide. 95 54

Exposure of rabbit pulmonary arterial smooth muscle cells to hydrogen peroxide cause dose-dependent stimulation of [14C] arachidonic acid (AA) release and enhancement of the cell membrane-associated phospholipase A2 activity as well as of the cell membrane-bound serine esterase activity tested against synthetic substrate p-tosyl-L-arginine methyl ester. While pretreatment of cells with serine protease inhibitors, viz. phenyl methyl sulphonyl fluoride, diisopropyl fluorophosphate and alpha-1-proteinase inhibitor, and antioxidant vitamin E prevents H2O2 stimulation of AA release and the cell membrane-bound serine esterase and PLA2 activities, that with actinomycin D and cycloheximide is devoid of any effect on H2O2 caused stimulation of AA release and the smooth muscle cell membrane associated serine esterase and PLA2 activities. Treatment of the smooth muscle cell membrane suspension with the serine protease trypsin markedly stimulates PLA2 activity. These results suggest that on exposure to H2O2 the smooth muscle cell membrane-bound serine esterase plays an important role in stimulating the cell membrane associated PLA2 activity thereby resulting in an increase in AA release.
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PMID:Role of serine esterase in hydrogen peroxide-mediated activation of phospholipase A2 in rabbit pulmonary arterial smooth muscle cells. 129 64

We have investigated the possible role of the fetal pituitary and ACTH in the control of the synthesis and post-translational processing of the enkephalin precursor, proenkephalin A (proEnk A), in the fetal sheep adrenal gland in late gestation. Fetal hypophysectomy (n = 8) or sham operations (n = 4) were performed between 109 and 118 days of gestation. At 138-139 days, either ACTH(1-24) (10.5 micrograms/0.24 ml saline per h, n = 4) was infused intravenously for 72 h into hypophysectomized fetal sheep or 0.9% (w/v) NaCl alone (0.24 ml/h, n = 4) was infused for 72 h into hypophysectomized fetal sheep and sham-operated animals. At the end of the infusion the pregnant ewe was killed and left or right adrenal glands (n = 12) were collected from the fetal sheep that were intact and given saline (Intact + sal; n = 4), hypophysectomized and given saline (Hx + sal; n = 4) and hypophysectomized and given ACTH (Hx + ACTH; n = 4). Each adrenal was homogenized in acid (acetic acid (1 mol/l)/HCl (20 mmol/l)/2-mercaptoethanol (0.2%)). After centrifugation, the supernatant was loaded onto a Sephadex G-75 column (2.0 x 50 cm), eluted at 80 ml/24 h and fractions were collected (5 ml, n = 42). An aliquot of each fraction (2 ml) was dried down prior to enzymatic digestion (trypsin/carboxypeptidase B) and oxidation with H2O2, and assay for methionine-O-enkephalin (immunoreactive Met-O-Enk).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of fetal hypophysectomy with or without ACTH replacement on the molecular weight profile of enkephalin-containing peptides in the adrenal medulla of the fetal sheep. 132 54

Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl radical (HO.) generating systems of xanthine oxidase (XO) + EDTA-Fe3+ and ascorbate + EDTA-Fe3+. Formation of bityrosine and loss of tryptophan were observed in the ascorbate + EDTA-Fe3+ system and carbonyl formation was induced by both systems. Mannitol and ethanol very strongly inhibited the carbonyl and/or bityrosine formation, indicating that the oxidative damage to BSA was due to HO(.). The sulfhydryl (SH) groups of BSA were very sensitive to the XO + EDTA-Fe3+ but not to the ascorbate + EDTA-Fe3+ system. Catalase but not hydroxyl radical scavengers or superoxide dismutase strongly inhibited the loss of SH groups, indicating that H2O2 is involved in their oxidation. Fragmentation of BSA was observed during exposure to the XO + EDTA-Fe3+ and ascorbate + EDTA-Fe3+ systems and the products presented a broad band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Little formation of amine groups was observed in these systems, indicating that little peptide bond cleavage occurred. BSA exposed to the ascorbate + EDTA-Fe3+ system was more readily degraded by trypsin than that exposed to the XO + EDTA-Fe3+ system. Elastase degraded BSA exposed to the ascorbate + EDTA-Fe3+ system but not to the XO + EDTA-Fe3+ system.
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PMID:Oxidative damage to bovine serum albumin induced by hydroxyl radical generating systems of xanthine oxidase + EDTA-Fe3+ and ascorbate + EDTA-Fe3+. 133 12


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