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)

At the level of ultrastructure, basement membranes (BMs) are usually described as thin layers of extracellular matrix comprised of an interwoven mat of fine 3-4 nm fibrils embedded in a granular matrix. In order to improve the resolution of the fibrillar components, we have carried out TEM studies on human glomerular BMs (GBMs) made acellular by sequential detergent solubilization. Some GBMs were pretreated with pronase, trypsin, or pepsin for 30 min to 72 h prior to preparation for microscopy. Our study shows that irrespective of which enzyme is employed, background granular matrix is first solubilized leaving a three dimensional fibrillar network comprised of 3-8 nm fibrils. Larger 7-8 nm fibrils are concentrated near subepithelial portions of the GBM and are most resistant to proteolysis. Smaller 3-4 nm fibrils are located primarily subjacent to endothelium and mesangial cells and are more protease-sensitive. An unexpected finding in pepsinized samples was a quasi-hexagonal fibrillocrystalline structure associated with mesangial matrix and subendothelial portions of the GBM. These data suggest that intrinsic fibrillar components of human GBMs are heterogeneously distributed throughout the thickness of their laminae densae. We speculate that the network consists of type IV collagen and that the hexagonal crystals may represent type VI or some previously unreported BM collagen type.
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PMID:Intrinsic fibrillar components of human glomerular basement membranes: a TEM analysis following proteolytic dissection. 249 69

The complete amino acid sequence of the p453-plasmid-mediated PIT-2 beta-lactamase (SHV-1) was determined. The protein contains 265 residues. Peptides resulting from digestions with trypsin, Staphylococcus aureus V8 proteinase, chymotrypsin and Lys-C proteinase and cleavage with CNBr were separated and purified by using reverse-phase h.p.l.c. The amino acid sequence of each peptide was manually determined with the dimethylaminoazobenzene isothiocyanate/phenyl isothiocyanate double-coupling method. The primary structure of PIT-2 beta-lactamase was compared with those of two closely related enzymes, namely TEM-1 beta-lactamase and the beta-lactamase of Klebsiella pneumoniae strain LEN-1. The PIT-2 beta-lactamase amino acid sequence was strongly retained, with respectively 68% and 88% homology. Thus PIT-2 enzyme could represent an evolutionary step between a chromosomally encoded beta-lactamase and the plasmid-mediated TEM beta-lactamases.
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PMID:Complete amino acid sequence of p453-plasmid-mediated PIT-2 beta-lactamase (SHV-1). 326 Apr 90

Sheep red blood cells sensitized by 7S, but not by 19S rabbit anti-Forssman antibodies, adhere and form rosettes on mouse macrophages and on a few monocytes and polymorphonuclear cells (PMN). When, however, C' factors from mouse serum are added to the antigen-19S antibody complex (EAC'), rosettes are formed on most mouse peritoneal macrophages and PMN and on a few monocytes. In addition EAC' also adheres to 10-25% of lymph node lymphocytes but not to thymus lymphocytes. EAC' prepared with 7S anti-Forssman antibodies has identical properties. The adherence of red cells induces an increase in the membrane activity of the leukocytes and causes injury to the red cells which rapidly become deformed and fragmented. Adherence of EAC' occurs at 37 degrees C and is minimal at 4 degrees C. Probably only the first four C' components are involved in this phenomenon as mouse serum deficient in C'5 or rabbit serum, deficient in C'6 can be used as a source of C' components. Treatment of EAC' with EDTA does not modify its leukocyte-adherence properties. The adherence of EAC' to the leukocytes is not inhibited in the presence of serum. The receptors for C' on macrophages, PMN, and monocytes differ from those found on lymphocytes. Rosette formation by EAC' on macrophages, PMN, and monocytes depends on divalent cations (Mg(++)) and can be reversed by Na(3)H EDTA, while adherence to lymphocytes is independent of these ions and occurs in the presence of 0.01 M Na(3)H EDTA. Both types of receptors for C' components are destroyed by trypsin treatment of the leukocytes, in contrast with the receptors for 7S antibodies on the same cells which persist after enzyme treatment.
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PMID:Receptors for complement of leukocytes. 417 27

Anaphylatoxin activity was derived from both human C'5 and C'3 molecules. This was achieved in the case of C'5 by interaction with trypsin or with EAC'4, (oxy)2a, 3. The smooth muscle-contracting material obtained from the treated C'5 was found to be a fragment of approximately 9,000-11,000 molecular weight. Its action was inhibited with antihistamine. The trypsinized C'5 also increased vascular permeability in guinea pig skin. When human C'3 was incubated with C'3 inactivator complex, which consists of a cobra venom protein and a beta-globulin of human serum, anaphylatoxin activity was observed. The activity was associated with a fragment cleaved from the C'3 molecule, having a molecular weight of between 6,000 and 15,000 as determined by gel filtration techniques. Similar activity was derived from C'3 by the C'3-converting enzyme in free or in cell-bound form. The C'5 anaphylatoxin failed to cross-desensitize guinea pig ileum to the contracting capacities of C'3 and guinea pig anaphylatoxin and vice versa. Anaphylatoxin prepared from C'3 by all methods mentioned above caused cross-desensitization to the other C'3 derivatives, but failed to desensitize to guinea pig anaphylatoxin.
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PMID:The derivation of two distinct anaphylatoxin activities from the third and fifth components of human complement. 438 23

A protein fraction (60-F), obtained from cell-free extract of living hemolytic streptococcus, Su-strain, by 50-60% saturation with ammonium sulfate, inhibited the de novo synthesis of nucleic acids and proteins in Ehrlich ascites carcinoma (EAC) cells. 60-F released RNA but not DNA from EAC cells. This cytotoxic or cytolytic effect of 60-F was substantiated morphologically by scanning and transmission electron microscopic (SEM and TEM) observations, showing that 60-F induced cellular changes such as a loss of microvilli, bleb formation, cell deformity and partial gap of cell membrane in EAC cells. In addition, it was found that 60-F was more stable in RPMI-1640 medium supplemented with fetal calf serum than in other various media examined and was sensitive to temperature, pH changes and trypsin digestion.
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PMID:Biochemical and electron microscopic observations of cytotoxic effect of a fraction from hemolytic streptococcus on Ehrlich ascites carcinoma cells. 618 69

The formation of EAC 4b2a is a two step reaction: first, the temperature- and time-independent binding of C2 to EAC4b2a resulting in EAC4b2 , secondly, the enzymatically triggered conversion of EAC4b2 to EAC4b2a . In the classical cascade of complement activation, the generation of C3 convertase activity is triggered by the C1 esterase, C1-s, which is part of C-1. Evidence is presented that the enzymes trypsin, chymotrypsin, plasmin, and pronase are also able to activate EAC4b2 to EAC4b2a . Kinetic studies showed that the formation of C3 convertase by these enzymes was dependent on concentration, temperature, and time. The optimal conditions were found as follows: trypsin, 2 micrograms/ml (final conc.) for 8 min at 23 degrees C; chymotrypsin 165 micrograms/ml for 18 min at 23 degrees C; plasmin 0.8 units/ml for 15 min at 23 degrees C; pronase 1.25 microgram/ml for 15 min at 23 degrees C. Even under optimal (tmax) conditions the number of generated EAC4b2a differed from enzyme to enzyme: trypsin (= 100%), pronase (58.3%), chymotrypsin (47.9%), and plasmin (12.9%). The enzymes were also able to generate C3 convertase activity from C2 which was adsorbed to EAC1i4b , a C1 inactivator treated and therefore hemolytically inactive intermediate ( EAC1i4b2 ). These findings underline the biological importance of C1 esterase replacing enzymes.
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PMID:Generation of the classical pathway C3 convertase (EAC4b2a) by proteolytic enzymes. 637 57

Mouse inflammatory macrophages from C57BL/6N mice were fused with BALB/c mouse-derived myeloma cells (the CANS series). The hybrids in the early period after cell fusion (8 weeks) showed no macrophage functions (chemotaxis, EA and EAC rosette-forming abilities, phagocytosis or lysozyme production). EA rosette-forming ability was observed when these hybrids were treated with trypsin, whereas other macrophage functions were not. After prolonged culture, the hybrids (12 clones of 13 randomly selected) showed all the macrophage functions along with chromosome loss. Myeloma cell functions (kappa light chain production) were found in the young hybrids soon after cell fusion but were absent in the aged hybrids. These results indicated that reexpression of macrophage properties, except for EA rosette-forming abilities, takes place after the loss of chromosomes or genes repressing the expression of macrophage functions.
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PMID:Expression of macrophage functions in hybrids of a myeloma cell line with inflammatory macrophages: evidence for negative control mechanisms in the expression of macrophage functions. 673 48

Receptors for C3b (C3R) in human spleen and kidney were studied using haemadsorption to cryostat sections. The indicator cells, ovine erythrocytes (E) coated with rabbit IgM antibody (A) and human C3b (EAC) adhered strongly to the glomeruli in renal tissue and to the white pulp of spleen. Titration experiments showed that avidity of the two populations of C3R was equal. Activity was independent of Ca++ and Mg++. Periodic acid, formaldehyde, high salt concentrations and trypsin abolished, whereas neuraminidase enhanced the activity. Various temperatures and pHs affected the two populations of C3R similarly. The results obtained indicate that the C3R in spleen and kidney are similar.
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PMID:Similarities of C3b receptors in human kidney and spleen. 679 Apr 44

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


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