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)

The surface properties of blood lymphocytes from treated myeloma patients and healthy controls were studied in vitro. The patients were tested 6 weeks after the last treatment to allow time for cells to recovery from possible drug toxicity. Peripheral-blood lymphocytes were tested for rosette formation with unsensitized sheep erythrocytes (E rosettes) and with complement and antibody-coated erythrocytes (EAC rosettes). The tests were duplicated using lymphocytes pretreated with trypsin. As others have noted, myelomatosis is associated with increased blood levels of EAC-rosette-forming cells and a marked reduction in E-rosette-forming cells. E-rosette formation was significantly increased by pretreatment of myeloma lymphocytes with trypsin. By contrast, enzyme-treated cells showed no significant change in EAC-rosette formation. These results suggest that the absolute number of circulating T cells is probably not reduced in myelomatosis, but that the surface of T cells is somehow modified so that a proportion of them lose the ability to form E rosettes.
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PMID:Enzyme-induced modification of the surface properties of lymphoid cells in malignant disease. I. Effect of trypsin on rosette formation by lymphocytes in myelomatosis. 696 55

Blood eosinophils from some patients with an eosinophilia have a higher capacity to bind to IgC antibody-coated red cells (EA) than blood eosinophils from normal people. Twenty per cent of eosinophils from normal blood bound EA, whereas eight of nine patients with hypereosinophilic syndromes and all nine patients with filariasis who were studied had blood eosinophils with EA rosette-forming capacities of between 42 and 89%. High EA binding capacity was reduced in culture, and prednisolone and cytochalasins A and B inhibited normal blood eosinophil EA binding. Normal blood eosinophils developed small increases in EA binding capacity in culture, but marked increases occurred after stimulation with soluble immune complexes, endotoxins and lipid A. Supernatants from granulocytes cultured with zymosan-C3b caused rapid increases in eosinophils EA binding capacity which also occurred with neuraminidase, pronase and trypsin. In vitro alterations in EA rosetting did not require protein synthesis and did not affect eosinophil phagocytic capacity for EA. Substances in culture which did not affect eosinophil EA rosetting capacity included sera from patients with eosinophils with high EA binding capacity and chemotactic substances. Cultured eosinophils also developed an increased capacity to form rosettes with EAC3b, and soluble immune complexes stimulated this further. Conversely, blood eosinophils formed less C3b rosettes when separated from heparinized blood in which C3 activation had occurred. CytochalasinA (but not B) irreversibly inhibited eosinophils EAC3b rosette formation. Trypsin also inhibited, but this effect was reversed within 30 min after washing. It was concluded that eosinophils from normal blood have an intrinsically lwo capacity to bind EA, but that in vivo and in response to stimulation in vitro their ability to bind complexed IgG can approach that seen with blood neutrophils. It is suggested that enzymes in granulocyte secretion products may cause the membrane changes which lead to high eosinophils EA binding capacity. This increase, which can occur separately from alterations in EAC binding or phagocytic capacity, may enable eosinophils to take part more effectively in inflammatory reactions in tissues.
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PMID:Enzymes altering the binding capacity of human blood eosinophils for IgG antibody-coated erythrocytes (EA). 699 78

The xylanase A (endo-1,4-beta-D-xylan xylanhydrolase) of the basidiomycete Schizophyllum commune was treated with the powerful carboxylate-modifying reagent 1-(4-azonia-4,4-dimethyl-pentyl)-3-ethylcarbodiimide iodide (EAC) in the presence of substrate. This treatment was followed by complete inactivation of the enzyme with [14c]EAC after the removal of excess reagent and protecting ligand. The inactivated enzyme was digested with endoproteinase Arg-C or trypsin, and peptides were separated and purified using reverse-phase high-performance liquid chromatography. Following sub-digestion of individual radioactive peptides with staphylococcal V8 protease and endoproteinase Lys-C, amino acid composition analysis and sequencing analysis revealed that the [14C]EAC label was bound exclusively to Glu87. Comparison of the primary sequences of related xylanase with that of xylanase A revealed that Glu87 is a highly conserved residue. Based on this similarity and the mechanism of carbodiimide action, Glu87 is proposed to act as the nucleophile in the catalytic mechanism of xylanase A. The possible environment of the putative catalytic glutamate residue was explored using hydrophobic-cluster analysis and secondary-structure prediction based on the primary sequence of xylanase.
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PMID:Identification of a glutamate residue at the active site of xylanase A from Schizophyllum commune. 790 49

A casein kinase released from activated human platelets phosphorylates a number of plasma proteins extracellularly, and that activation of platelets in systemic lupus erythematosus patients parallels an increase in the phosphate content of plasma proteins, including C3. The present study was undertaken to characterize this platelet protein kinase and to further elucidate the effect(s) on C3 function of phosphorylation by platelet casein kinase. The phosphate content of human plasma C3 was increased from 0.15 to 0.60 mol phosphate/mol of C3 after platelet activation in whole blood or platelet-rich plasma. The platelet casein kinase was distinct from other casein kinases in terms of its dependence on cations, inhibition by specific protein kinase inhibitors, and immunological reactivity. C3 that had been phosphorylated with platelet casein kinase was tested for its susceptibility to cleavage by trypsin or the classical and alternative pathway convertases and its binding to EAC and IgG. Phosphorylation did not affect the cleavage of C3 into C3a and C3b, but the binding of fragments from phosphorylated C3 to EAC14oxy2 cells and to IgG in purified systems and in serum was increased by 1.6-4.5 times over that of unphosphorylated C3. A covariation was seen between the enhanced binding of C3 fragments to IgG after phosphorylation and an increased ratio of glycerol/glycine binding, from 2.0 for unphosphorylated C3 to 4.9 for phosphorylated C3. The present study suggests that an overall effect of phosphorylation of C3 by platelet casein kinase is to enhance the opsonization of immune complexes.
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PMID:Alterations in C3 activation and binding caused by phosphorylation by a casein kinase released from activated human platelets. 1035 96


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