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)

Modifications in the distribution of the binding sites for concanavalin A (Con A) were studied on trypsin isolated living guinea pig keratinocytes. Fluorescein-labelled Con A was used and the in vitro procedure has included short-term cultures, experiments at 37 degrees C and 4 degrees C, the study of colchicine and vincaleucoblastine effects. It was possible to induce different patterns of staining corresponding to distinct redistribution of Con A binding sites; the distinct redistribution was correlated to the effects of Con A, colchicine and vincaleucoblastine. These findings demonstrated that the system used was appropriate to the study of some dynamic events on the keratinocytes membranes.
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PMID:Dynamic redistribution of concanavalin A binding sites on isolated guinea pig keratinocytes. 8 36

One eye of a 21-year-old patient with proliferative diabetic retinopathy was available for clinicopathologic correlation. The fluorescent spots in a fluorescein angiogram were correlated with the changes in color fundus photographs and with the corresponding histologic findings in a trypsin digest preparation of the retina. A round, regular fluorescent spot was the most reliable diagnostic indicator of retinal capillary microaneurysms, although some microaneurysms appeared as irregular fluorescent spots, tiny fluorescent spots, or dark silhouettes with or without fluorescent halos. Very large fluorescent spots correlated with very large irregular pouches that may represent intraretinal neovascularization. Fluorescein angiography was considerably more sensitive than color fundus photography for the detection of retinal capillary microaneurysms.
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PMID:Clinicopathologic correlations in diabetic retinopathy. II. Clinical and histologic appearances of retinal capillary microaneurysms. 88 82

Unilateral optic nerve transection without damage to the intraocular circulation was performed on thirteen cats. Fluorescein angiograms, trypsin digestion, and histologic preparation of the retinas were carried out. No changes in the retinal circulation and angioarchitecture were observed. These findings were compared to those reported in humans with comparable optic nerve lesions. We conclude that optic nerve transection does not cause retinal vascular alteration and this fact may be of pertinence to posterior ocular damage in glaucoma.
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PMID:Optic nerve transection in cats: effect on retinal vessels. 109 61

Fluorescein 5'-isothiocyanate binds almost selectively at the active site of lamb liver NADP-dependent 6-phosphogluconate dehydrogenase causing the inactivation of the enzyme. The substrate and the coenzyme protect against the loss of catalytic activity. The enzyme derivative was digested with trypsin, the labelled peptide was isolated by h.p.l.c. and its amino acid analysis allowed to establish that the inactivator binds to lysine 166 at the active site of the protein.
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PMID:Identification of the lysine residue involved in the inactivation of lamb liver 6-phosphogluconate dehydrogenase by fluorescein 5'-isothiocyanate. 181 97

Fluorescein 5'-isothiocyanate has been used to label ouabain sensitive and insensitive (Na,K)-ATPases from lamb and rat kidney, respectively. The labeled enzymes were digested with trypsin to generate soluble peptides, which were purified by high performance liquid chromatography and sequenced on a gas phase sequenator. The sequence of the labeled peptide from both species is His-Leu-Leu-Val-Met-Lys-Gly-Ala-Pro-Glu-Arg. Thus, it appears that the primary structure of the fluorescein 5'-isothiocyanate reactive site, and therefore presumably the ATP binding site, is completely conserved in ouabain sensitive and ouabain insensitive (Na,K)-ATPases.
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PMID:The amino acid sequence of the fluorescein isothiocyanate reactive site of lamb and rat kidney Na+- and K+-dependent ATPase. 609 47

Monkey kidney cells productively infected with Yaba tumor poxvirus clearly exhibit plasma membrane alterations when treated with both fluorescein-labeled and unlabeled concanavalin A. The convanavalin A-mediated cytoagglutination reaction for Yaba-infected Jinet and CV-1 cells increased linearly from 12 to 16 h post-infection, reaching a maximum by 24-28 h. Treatment of either Yaba-infected CVC-1 or Jinet cells with methyl-D-glucopyranoside before or after addition of concanavalin A completely blocked or reversed the cytoaglutination response. Trypsin treatment of uninfected CV-1 or Jinet cells enhanced concanavalin A-mediated cytoagglutination properties. Conversely, trypsin treatment of Yaba-infected Jinet cells resulted in a reduced cytoagglutination response. Increasing temperature and lectin concentration enhance concanavalin A-mediated cytoagglutination for uninfected, trypsin-treated and Yaba-infected CV-1 cells. Cytosine arabinoside has little or no effect on the Yaba-induced cell cytoagglutination reaction while cycloheximide blocks the cytoagglutinatin response if added prior to 12 h post-infection. Fluorescein-labeled concanavalin A binding studies have revealed that at 4 degrees C, Yaba-infected CV-1 cells display a predominantly 'patchy' pattern of topological fluorescence, while trypsin-treated and uninfected CV-1 cells at 4 degrees C display a uniform pattern of fluorescence binding. Patchy fluorescence, indicative of concanavalin A-suspeptible, receptor-site clustering on the surface membrane, was reduced 50% if Yaba-infected CV-1 cells were treated with glutaraldehyde (2.5%) before addition of fluorescein-labeled concanavalin A at 4 degrees C. Similar pre-fixatin of trypsin-treated CV-1 cells resulted in uniform, fluorescent labelling patterns at all assay temperatures.
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PMID:Surface membrane redistribution and stabilization of concanavalin A-specific receptors following Yaba tumor poxvirus infection. 625 May 95

Fluorescein isothiocyanate is a highly specific inhibitor of the Ca2+-ATPase from sarcoplasmic reticulum. The Ca2+ pumping is inhibited completely at a fluorescein isothiocyanate concentration half that of the ATPase protein, indicating that the protein is at least a dimer. ATP protected specifically against fluorescein isothiocyanate inhibition, indicating that fluorescein isothiocyanate may react at the nucleotide binding site of the ATPase (probably with a reactive lysine residue). The fluorescein is incorporated almost exclusively into the 105 kdalton catalytic polypeptide of the ATPase and digestion by trypsin gives rise to a fluorescein-labelled 45 kdalton fragment. Conformational changes induced by addition of Ca can be studied conveniently with the fluorescein-labelled ATPase.
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PMID:Indications for an oligomeric structure and for conformational changes in sarcoplasmic reticulum Ca2+-ATPase labelled selectively with fluorescein. 645 Jun 19

Monosaccharides, lectins, periodate, trypsin and neuraminidase were used to analyse the process of adhesion of Giardia duodenalis trophozoites to IEC cells, an intestinal epithelial cell line. Addition of N-acetyl-glucosamine, N-acetyl-galactosamine, galactose and fucose to the interaction medium inhibited attachment of the parasites to the epithelial cells. Experiments in which the parasites or epithelial cells were treated before interaction showed that these monosaccharides interfered with both cell surfaces. Trypsin-sensitive, but not neuraminidase-sensitive, groups exposed on the cell surface are important for the parasite-epithelial cell association. Fluorescein isothiocyanate (FITC)- or colloidal gold-labeled lectins were used to analyse the distribution of carbohydrates on the surface of G. duodenalis and epithelial cells. It is important to stress here the presence of fucose on the parasite surface. Treatment of the cells with lectins was also used to analyse the role of carbohydrate-containing macromolecules in the parasite-cell interaction.
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PMID:Role of surface components in the process of interaction of Giardia duodenalis with epithelial cells in vitro. 807 20

Increased numbers of mast cells (MCs) and lymphocytes infiltrating in basal cell carcinomas (BCCs) have been observed. The presence of these infiltrating cells has been considered a sign of an immunologic anti-tumor response in the host, but the relationship of these two cell populations has not been examined. To elucidate this possible relationship, 30 non-ulcerated BCCs were analyzed. Frozen sections of the tumors were stained with monoclonal antibodies for Langerhans' cells, lymphocyte subsets and natural killer cells. Fluorescein isothiocynate (FITC)-avidin as well as anti-tryptase and anti-CD45RO monoclonal antibodies were used on formalin-fixed, paraffin-embedded sections for mast cell and T cell identification, respectively. B cells and natural killer cells were rarely observed in these tumors. MCs and T cells were quantified by direct enumeration and expressed as number of cells per high power field (hpf). FITC-avidin and anti-tryptase antibodies were equivalent in their ability to identify MCs. MC content in BCCs ranged from 1.0 to 31 cells/hpf. The number of T cells ranged from 0 to 50 cells/hpf with helper/suppressor cell ratios of 0.2 to 10. There was no correlation between helper/suppressor ratios and mast cell numbers; however, an inverse relationship was observed between the numbers of T cells and the number of mast cells in these tumors. These studies indicate that T cells and MCs are the primary immune cell populations responding to BCCs, and that decreased numbers of T cells are associated with more aggressive tumors.
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PMID:Immune-associated cells in basal cell carcinomas of skin. 872 48

[3H]P1075 binding to membrane preparations of rabbit skeletal muscle were observed in the presence of nucleotide triphosphates or diphosphates but not AMP, cAMP, adenosine, tripolyphosphate, or pyrophosphate. Nonhydrolyzable or poorly hydrolyzable ATP analogs inhibited MgATP-supported binding. The EC50 value for MgATP-supported binding (0.4 mM) was decreased approximately 10-fold in the presence of an ATP-regenerating system, and significant metabolism by membrane nucleotidases was confirmed by high performance liquid chromatographic analysis. [3H]P1075 bound to skeletal muscle with a Kd value of 37 +/- 3 nM and a Bmax value of 280 +/- 14 fmol/mg of protein. [3H]P1075 binding to subcellular fractions was highest in membranes enriched in T tubules. Specific binding was reversible, trypsin-sensitive, maximal at pH 8, and stereoselective for the (3S,4R)-enantiomer of cromakalim. Potassium channel openers exhibited a rank order of potency of P1075 > pinacidil > levcromakalim = BMS-180448 > nicorandil > diazoxide = BRL 38226. Fluorescein analogs (ethyleosin, phloxine B, and rose bengal) were relatively potent inhibitors of binding (Ki = 200-300 nM). The potassium channel openers cromakalim and BMS-180448 were competitive inhibitors of [3H]P1075 binding. In contrast, rose bengal and the ATP-regulated potassium channel antagonist glyburide increased the rate of [3H]P1075 dissociation in a manner consistent with noncompetitive interaction.
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PMID:Nucleotide regulation and characteristics of potassium channel opener binding to skeletal muscle membranes. 928 10


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