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)

Human red blood cells can bind in vitro to autologous peripheral blood lymphocytes forming auto-rosettes. The percentage of rosett-forming cells (A-RFC) depends on erythrocyte ageing in vivo. Old untreated cells given an A-RFC percentage lower as compared with the young ones. The same age groups of cells treated with neuraminidase show a parallel increase of A-RFC as compared with untreated cells. No significant difference is found between young and old cells with high concentrations of neuraminidase. The rosetting formation is inhibited by the pre-treatment of lymphocytes with erythrocyte glycopeptides released by trypsin. This suggests that auto-rosetting is mediated by erythrocyte surface glycopeptides in which sialic acid plays a role directly or not.
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PMID:Effects of ageing, surface sialic acid and glycopeptides of erythrocytes on auto-rosettes in man. 73 12

The receptor for FC(IgG) on chicken lymphoid cells was investigated by EA rosette techniques using sheep erythrocytes sensitized with a sub-agglutinating dose of anti-sheep erythrocyte (SRBC) chicken serum. Chicken lymphocytes did not form rosettes with SRBC coated with rabbit antibody, and human and mouse lymphocytes did not bind SRBC sensitized with chicken antibody. Only avian sera were effective in blocking the Fc receptor. Similarities between chicken and mammalian Fc receptors were demonstrated as both are pronase sensitive, trypsin resistant, and are distinct from surface immunoglobulin. Fc receptors were also distinguished from avian bursa- and thymus-specific antigens. Additional Fc receptor-bearing cells were revealed in bursa, spleen and bone marrow lymphocytes after neuraminidase treatment.
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PMID:Fc receptor-bearing lymphoid cells in the chicken. I. Characterization of the Fc(IgG) receptor. 74 17

The attachment of rat hepatocytes to polystyrene-adsorbed serum protein is relatively insensitive to inhibitors such as dextran sulphate, cycloheximide, colchicine and cytochalasin B, and enzymes like trypsin and neuraminidase, but it is strongly dependent on divalent cations. Mg2+ supports attachment better than Ca2+, but a combination of both is required for maximal attachment. The attachment is very temperature-sensitive, with a biphasic Arrhenius plot indicating an activation energy of 123 kJ/mol above 34 degrees C and 374 kJ/mol below 34 degrees C. The adsorbed attachment-promoting serum factor is inactivated by trypsin, or by Ca2+-dependent proteases which contaminate commercial preparations of collagenase. The adsorbed factor is resistant to treatment with glutaraldehyde, neuraminidase and heating to 90 degrees C, whereas the same factor in the unadsorbed state (in serum) is destroyed by heating to 70 degrees C. The factor in serum is unable to compete with the adsorbed factor for cell binding, hence it would appear that adsorption to polystyrene induces the active, heat-resistant conformation of the factor.
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PMID:Effect of temperature and divalent cations on the substratum attachment of rat hepatocytes in vitro. 74 33

Critical mixtures of aqueous solutions of polymers separate into two or more immiscible phases. Particulate materials distribute in such phase systems generally between one bulk phase and the interface between bulk phases. The distribution is described by a simple partition law, and is quantitatively determined by, inter alia, the nature of the particle surface, particularly net electrical charge. The partition behaviour of various cells, native or modified by treatment with trypsin, neuraminidase or maleic anhydride, correlate strongly with electrophoretic mobility. Partition behaviour and electrophoretic mobility are both dependent upon cell surface charge. Thus, in appropriate conditions, changes in surface charge may be registered as changes in partition.
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PMID:Cell surface charge correlation of partition with electrophoresis. 76 Aug 12

Critical mixtures of aqueous solutions of polymers can be separated into two or more immiscible phases. Particulate materials are distributed in such phase systems generally between one bulk phase and the interface between bulk phases. The distribution is described by a simple partition law and is quantitatively determined by temperature, interfacial tensions, the electromotic potential difference between phases and the nature of the particle surface. The effects on transfacial potential differences of varying polymer, NaCl and sodium phosphate concentrations in dextran/polyethylene glycol systems were studied: increase of polyethylene glycol concentration increased the potential; addition of up to 40 mM NaCl progressively reduced the potential to zero: very small (less than 10 mM) concentrations of sodium phosphate buffer increased the potential, but further increase caused a fall in potential, which was less marked than that caused by equivalent concentrations of NaCl. The partition properties of a variety of cells, native or modified by treatment with trypsin, neuraminidase or maleic anhydride, were studied. In systems containing greater than 40 mM NaCl no difference in partition patterns for modifications of each cell type was observed. In systems containing no NaCl the partition pattern was highly dependent on the nature of the modification. From the behaviour of such models, polymer-electrolyte phase systems suitable for study of cell surface modification involving change, or no change, in net surface have been identified.
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PMID:Cell partition: a study of parameters affecting the partition phenomenon. 76 Aug 20

Low concentrations of protease and trypsin reduced the electrophoretic mobility (EPM) of thymocytes; with higher concentrations it was normal or above. Differences in membrane structure of thymocytes, T and B cells was found as B cells showed no reduction while T cells gave intermediate values. Further the reduction was greater with protease than with trypsin. Formalin fixation increased the EPM of all normal cell types to a similar degree. The EPM of proteolytically treated thymocytes and B cells was increased to a similar level and to a greater degree than neuraminidase-treated thymocytes. Small amounts of sialic acid were detected in the supernatant after proteolytic treatment of thymocytes. Protease reduced the binding of anti-lymphocyte serum, while no definite effect was obtained with trypsin. Neither sublytic doses of phospholipase C nor ribonuclease appeared to change the EPM.
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PMID:Electrophoresis of lymphoid cells. Differences in the cell membrane structure of murine thymocytes, T and B cells revealed by enzyme and formalin treatment. 76 20

The chorionic villi of placentas, 10 to 40 weeks of gestation, were examined for A and B blood group antigens with an immunoferritin technique. No specific ferritin attachment was shown on the plasma membrane of the villous trophoblasts. Furthermore, after trophoblast cell-surface mucosubstances (perhaps the barrier of the placental antigenicity, according to some authors) were digested with several enzymes, such as neuraminidase, hyaluronidase, chondroitinase ABC, pepsin, trypsin, and pronase, no ferritin tagging was observed on the plasma membrane of the villous trophoblasts. We have concluded that our failure to detect the A and B blood group antigens was not due to the masking of antigens by mucosubstance coating the trophoblasts, but was due to the intrinsic deficit of those antigens in the plasma membrane of the human trophoblasts.
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PMID:Innumoelectron microscopy of the human chorionic villus in search of blood group A and B antigens. 79 65

Agglutination of thymocytes and B-cells with anti-lymphocyte serum subsequent to treatment of the cells with trypsin or neuraminidase was slightly and similarly increased, independent of the effect on the surface charge shown previously. The enzymatic treatment did not increase capping of antiserum binding sites. Agglutination caused by binding of IgG antibodies of anti-lymphocyte serum was not accompanied by change in the net surface charge. Neither did binding of the mitogens phytohaemagglutinin, concanavalin A or poke-weed mitogen influence the surface charge of the cells.
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PMID:The effect of anti-lymphocyte serum, mitogens and enzymatic treatment on the agglutination and surface charge of lymphoid cells. 79 95

Nerve growth factor (NGF) receptor binding in membrane fractions of rabbit superior cervical ganglia has been measured after treatment with a variety of enzymes, protein-modifying reagents, and ions. Receptor binding is degraded by low concentrations of trypsin but is much less sensitive to alpha-chymotrypsin. Low concentrations of phospholipase A from Vipera russelli decrease NGF receptor binding by lowering the number of binding sites, while phospholipase A preparations from Crotalus terrificus terrificus and bee venom do not affect binding. Phospholipase C and D, neuraminidase, DNase, and RNase have minimal effects on receptor binding. NGF receptor binding appears to be absolutely dependent upon calcium ion. Removal of calcium from the incubation medium greatly reduces binding as does treatment with EDTA. Maximal receptor binding occurs at 5 mM calcium. Magnesium and sodium are unable to substitute for calcium. Receptor binding is greatly reduced by treating membranes with 2-hydroxy-5-nitrobenzyl bromide, 2-methoxy-5-nitrobenzyl bromide, diazonium tetrazole, and tetranitromethane. NGF receptor sites can be protected from 2-hydroxy-5-nitrobenzyl bromide by incubation with NGF.
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PMID:Nerve growth factor receptor binding. Influence of enzymes, ions, and protein reagents. 80 4

Exposure of mycobacterial growth inhibitory factor (MycoIF) to trypsin, chymotrypsin, or neuraminidase decrease its ability to produce intracellular inhibition of mycobacterial growth within macrophages, suggesting that MycoIF was a glycoprotein. MycoIF was unaffected by deoxyribonuclease or ribonuclease. Supernatant fluids from antigenically stimulated H37Ra-immunized mouse spleen cells exposed to puromycin were unable to produce significant intracellular inhibition. This indicated that the presence of MycoIF activity in supernatant fluids required protein synthesis. The filtration of MycoIF-containing supernatant fluids on Sephadex G-150 demonstrated that significant MycoIF activity appeared only in those fractions which eluted on the downward side of the serum albumin peak. Based on protein standards filtered through the Sephadex gel, the molecular weight of MycoIF was calculated to be between 20,000 and 35,000. These calculations assumed that MycoIF is a globular protein. Attempts to purify MycoIF by anion exchange chromatography (diethylaminoethylcellulose) was not successful.
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PMID:Molecular weight and other characteristics of mycobacterial growth inhibitory factor produced by spleen cells obtained from mice immunized with viable attenuated mycobacterial cells. 81 60


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