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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contribution of activated oxygen species to neutrophil-mediated degradation of basement membrane collagen was investigated. In preliminary experiments, pre-exposure of either albumin or glomerular basement membrane to neutrophil myeloperoxidase with H2O2 and chloride increased their susceptibility to proteolysis 2-3-fold. In the basement membrane model, neutrophils are stimulated by trapped immune complexes to adhere, produce oxidants and degranulate. Degradation, measured as the amount of hydroxyproline solubilised, was due to neutral proteinases, particularly elastase, and depended on cell number and the amount of proteinase released. Experiments with oxidant scavengers and inhibitors and with neutrophils from donors with chronic granulomatous disease or myeloperoxidase deficiency showed that oxidants did not affect degradation of the basement membrane when this was measured on a per cell basis. However, oxidative inactivation of the released granule enzymes occurred. Activities of elastase, beta-glucuronidase and lysozyme were 1.5-2-times higher in the presence of catalase, but were unaffected by superoxide dismutase or hydroxyl radical scavengers. Inactivation did not occur with chronic granulomatous disease or myeloperoxidase deficient neutrophils. When related to the activity of released elastase, or to other degranulation markers, collagen degradation was decreased in the presence of catalase, or with chronic granulomatous disease or myeloperoxidase deficient cells. This implies that the basement membrane was made more digestible by myeloperoxidase-derived oxidants, as occurred in the cell-free experiments. Taken together, the results indicate that neutrophil oxidants have two opposing effects. They increase the susceptibility of the collagen to proteolysis and inactivate the proteinases responsible.
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PMID:The effect of oxidants on neutrophil-mediated degradation of glomerular basement membrane collagen. 302 26

Recombinant human tumour necrosis factor alpha (rHuTNF alpha) was shown to inhibit human neutrophil migration in the presence or absence of a chemotactic gradient generated with the tripeptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), at doses of 20-100 U/10(6) cells. In contrast, neither recombinant human interleukin-1 alpha (rHuIL-1 alpha), rHuIL-1 beta, human leucocyte-derived IL-1 alpha (1HuIL-1 alpha) nor 1HuIL-1 beta contained neutrophil migration inhibition properties. However, both the interleukins (1HuIL-1 alpha, 1HuIL-1 beta and rHuIL-1 alpha) and rHuTNF alpha stimulated a neutrophil respiratory burst and significantly elevated the neutrophil respiratory response to fMLP (measured as chemiluminescence and H2O2 production). The stimulatory effects were observed at doses of between 5 and 100 U/5 x 10(5) cells. A characteristic feature of the effects of the cytokines was the range of variation observed in neutrophil responses from different individuals. However, a concentration-related effect was observed with each experiment, delineating suboptimal, optimal and supra-optimal cytokine concentrations. Neutrophils treated with rHuTNF alpha and rHuIL-1 alpha and washed free of exogenous cytokine retained the capacity to show an enhanced response to fMLP. Pretreatment of cells with cytochalasin B enhanced their response to fMLP, and this response was further increased if the cells had also been pretreated with the cytokines. The response to phorbol myristate acetate was also enhanced by rHuTNF alpha and rHuIL-1 alpha. The effects of these cytokines on neutrophils could be abolished by boiling the preparation but not by treating it with polymixin B, suggesting that bacterial lipopolysaccharide was not responsible for the activity of these preparations. The rHuIL-1 alpha increased the release of lysozyme, beta-glucuronidase and myeloperoxidase initiated by cytochalasin B/fMLP, while rHuTNF alpha only increased lysozyme release.
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PMID:Effects of tumour necrosis factor alpha and interleukin-1 alpha and beta on human neutrophil migration, respiratory burst and degranulation. 328 22

Culture medium conditioned by mononuclear leucocytes (MNL) stimulated by formalin-fixed heat-killed Staphylococcus aureus (sCM) modulated a number of neutrophil functions. The sCM inhibited the locomotion of human neutrophils in both the presence and absence of a chemotactic gradient generated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It also stimulated the oxygen-dependent respiratory burst as assessed by its ability to stimulate basal H2O2, superoxide and chemiluminescence production by neutrophils. Neutrophils treated with sCM also showed increased release of lysozyme but not beta-glucuronidase. In addition, the sCM-treated neutrophils showed a potentiated response to stimuli that bind surface receptors, i.e. FMLP and opsonized zymosan. The effects of sCM and either of the stimuli were synergistic. Examination of lysosomal enzyme release showed that sCM enhanced the release of lysozyme and beta-glucuronidase induced by either FMLP/cytochalasin B or zymosan. The response to phorbol myristate acetate (PMA), which bypasses the surface receptor, was also stimulated but compared poorly with the FMLP response. The sCM effects on the FMLP-induced chemiluminescence response occurred even when FMLP addition was delayed for 4 hr. Cells treated with sCM and washed retained the ability to show an enhanced FMLP response. The neutrophil-modulating activity was not produced by MNL cultured in the absence of bacteria.
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PMID:Staphylococcus aureus-stimulated human mononuclear leucocyte-conditioned medium augments the basal and stimuli-induced neutrophil respiratory burst and degranulation. 357 Mar 57

The trifluoroethanol-induced unfolding of hen egg-white lysozyme was studied by circular dichroism. It was shown that if the H2O/trifluoroethanol ratio is above 10:1 (v/v), the unique three-dimensional structure of the protein is not affected, whereas within the ration 10:1-2.8:1 (v/v), this structure is partially unfolded. At the ratio 2.4:1 (v/v), the native conformation of lysozyme is completely disrupted and the conformational transition fits a two-state model. A similar effect was observed for the trifluoroethanol-induced unfolding of the lysozyme-(GlcNAc)3 complex. Within the H2O2 trifluoroethanol ratio 15:1-5.5:1 (v/v), the characteristic intensities of the Cotton effects which arise from the association of (GlcNAc)3 with the active site of lysozyme, diminished and approached those exhibited by lysozyme itself at the same H2O trifluoroethanol ratios. This shows that (GlcNAc)3 is released from the protein surface in early stages of the unfolding process. At the ratio 2.4:1 (v/v), the lysozyme-(GlcNAc)3 complex was completely disrupted and the protein unfolded. It is suggested that a considerable alteration in hydration of the lysozyme molecule caused by trifluoroethanol increases protein surface fluctuations, causing the release of (GlcNAc)3 from the active site of lysozyme.
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PMID:Early stages in the trifluoroethanol-induced unfolding of hen egg-white lysozyme and its complex with (GlcNAc)3. 397 Sep 38

Human colostral macrophages stimulated by opsonized zymosan or phorbol myristate acetate (PMA) released superoxide anions (O2-) and hydrogen peroxide (H2O2) with activities comparable to those of monocytes and about one-fourth of those of polymorphonuclear leukocytes (PMNL) of blood. The O2- -forming oxidase in the macrophages stimulated by PMA was dependent on NADPH as an electron donor with an apparent Km value for NADPH of 27.6 +/- 4.0 microM, which is comparable to those obtained for the stimulated monocytes and PMNL of blood. The Vmax was 1.86 +/- 0.33 nmol O2/min/10(6) cells, which is essentially the same as that of monocytes and about half of that of PMNL. p-Chloromercuribenzoate or cetyltrimethylammonium bromide completely inhibited oxidases of all three types of phagocytes. A b-type cytochrome was identified in the macrophages but the concentrations in the macrophages and monocytes were less than half of that in PMNL. These results suggest that the differences in the O2- -forming activities of the three types of phagocytes are quantitative rather than qualitative. The macrophages and monocytes showed very low activities of myeloperoxidase [EC 1.11.1.7] in contrast to PMNL. The activity of beta-glucuronidase [EC 3.2.1.31] in the macrophages was much higher than those of the monocytes and PMNL, but little difference was observed in the activities of lysozyme [EC 3.2.1.17], catalase [EC 1.11.1.6] and superoxide dismutase [EC 1.15.1.1] among the three types of phagocytes examined. Electron micrographs of the macrophages showed little increase of vacuoles upon exposure to PMA, in contrast to the cases of monocytes and PMNL.
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PMID:Oxygen metabolism of human colostral macrophages: comparison with monocytes and polymorphonuclear leukocytes. 608

A number of cytochemical parameters of the hemocytes of larval Galleria mellonella, an insect frequently used as a model by comparative cellular immunologists, are described. Cytochemical methods were used to quantify hemocyte granule-associated components, the results are compared to those obtained for leukocytes from higher animals. Granulocytes contained a population of nonlysosomal granules rich in mucopolysaccharide not seen in plasmatocytes. The numbers and dimensions of these granules showed a positive correlation to cell size, probably reflecting a developmental sequence in granulocyte maturation. Both granulocytes and plasmatocytes had other granules containing the typical lysosomal enzymes, acid phosphatase, beta-glucuronidase, esterase, and lysozyme. The nonlysosomal enzyme alkaline phosphatase was not found in Galleria hemocytes; it is also absent from vertebrate monocytes, macrophages, and immature polymorphonuclear leukocytes. Insect hemocytes appear to lack certain components of antibacterial systems typical of mammalian blood cells, such as H2O2-generating systems, cationic proteins, and myeloperoxidase. The bactericidal mechanisms of hemocytes probably involve lysozyme, as well as other biologically active cellular and humoral factors unique to insects.
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PMID:Observations on the cytochemistry of the hemocytes of an insect, Galleria mellonella. 618 80

Incorporation of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), the principal mutagen in a tryptophan pyrolysate, into bovine serum albumin was catalyzed by myeloperoxidase. Hydrogen peroxide was essential for the incorporation reaction and albumin was required for optimal incorporation of Trp-P-2 into protein. Other various proteins, such as histone, lysozyme, cytochrome c, and gamma-globulin could also incorporate Trp-P-2, but poly(L-Arg), poly(L-Lys), and poly(L-Glu) could not. The incorporation of Trp-P-2 into albumin was inhibited by L-tyrosine and L-tryptophan, but not by other amino acids. Trp-P-2 incorporated into albumin was not released from the protein by treatment with 0.3 N HCl, or 0.3 N NaOH for 2 h at 35 degrees C, or with 1% sodium dodecylsulfate for 2.5 min at 100 degrees C. On electrophoresis on polyacrylamide containing sodium dodecylsulfate or urea and on chromatography on Sepharose CL-6B in 6 M guanidine/HCl, Trp-P-2 incorporated into albumin or lysozyme migrated with these proteins. These findings indicate that Trp-P-2 is covalently bound to these acceptor proteins.
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PMID:Myeloperoxidase-catalyzed binding of 3-amino-1-methyl-5H-pyrido[4,3-b]indole, a tryptophan pyrolysis product, to protein. 625 79

Various human and mouse myeloid leukemia cell lines can differentiate to mature myeloid or monocytoid cells in response to different agents. The myeloblastic leukemia of the RFM/Un mouse (the RF.AML line) was studied here to determine its ability to differentiate after in vitro and in vivo treatment. The RF.AML cells were passed in vivo by i.v. or i.p. injection of freshly harvested leukemic spleen cells or in vitro-passaged leukemia cells. The cells proliferated in the spleen and peritoneal cavity. The RF.AML cells had the appearance of myeloblasts or myelomonoblasts on Wright's stain, had slight positivity for peroxidase, and lacked staining for nonspecific esterase. The cells grew in suspension in vitro with a doubling time of 48 hr. Various phorbol diester tumor promotors inhibited proliferation and incorporation of thymidine into the RF.AML cells. Phorbol myristate acetate (10 to 100 nM) caused the cells to adhere to plastic, and enhanced the phagocytic ability of the cells for Candida albicans. The RF.AML cells had specific receptors for phorbol dibutyrate, binding 0.37 +/- 0.03 (S.E.) pmol of [3H]phorbol dibutyrate/10(6) cells after a 2-hr incubation at 4 degrees with 50 nM [3H]phorbol dibutyrate. Thirty-three to 300 nM dexamethasone caused 19 to 37% of the cells to become nonspecific esterase positive and enhanced their phagocytosis of C. albicans. Likewise, 0.5 or 1.0 microM 13-cis-retinoic acid, or 0.6 or 1.2% dimethyl sulfoxide enhanced the phagocytic ability of the RF.AML cells but had no effect on the adherence, proliferation, or nonspecific esterase activity. None of the treatments induced lysozyme activity in the cells or rendered the RF.AML cells able to produce H2O2 in response to phorbol myristate acetate treatment in vitro. In vivo treatment of mice with RF.AML present with phorbol myristate acetate or dexamethasone did not induce differentiation of the RF.AML cells or alter the survival of the animals. Thus, although the RF.AML cells differentiate in vitro in response to various agents, in vivo differentiation was not seen in this model.
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PMID:Comparison of in vitro and in vivo differentiation of myeloblastic leukemia of the RFM/Un mouse. 659 93

Neutrophils from the synovial fluid (SFN) of 10 patients with active rheumatoid arthritis (RA) were investigated to determine the generation of oxygen intermediates (OI) (O2-, H2O2, OH .), chemiluminescence, and lysosomal enzymes (lysozyme and beta-glucuronidase). Lymphocytes from healthy individuals were cocultured at 37 degrees C for 17 hr with SFN from the patients and the number of OKT4+, OKT8+, and OKT3+ cells and the response to mitogens were determined. A markedly increased OI and slightly elevated lysosomal enzyme levels were observed in SFN from patients. Coculture of lymphocytes with SFN resulted in a decreased number of OKT4+ and OKT8+ cells and a greatly reduced response to Con A and mildly diminished response to PHA, while OKT3+ cells were not affected. The simultaneous addition of superoxide dismutase and catalase restored the impairment of monoclonal antibody reaction and lymphocyte responsiveness almost to control levels. It is suggested that the disturbed immunoreactivity of synovial fluid lymphocytes from RA patients may be due to increased OI generated by stimulated neutrophils.
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PMID:Effect of stimulated neutrophils from the synovial fluid of patients with rheumatoid arthritis on lymphocytes--a possible role of increased oxygen radicals generated by the neutrophils. 660 65

The following enzyme activities were measured in cell lysates and supernatants from mouse peritoneal macrophages incubated with products of cultured tumour and other cells: acid phosphatase, beta-D-glucuronidase, N-acetyl-D-glucosaminidase, muramidase (lysozyme), lactic dehydrogenase (supernatant only) and plasminogen activator (supernatant only). There were no noteworthy changes in enzyme activities. Hydrogen peroxide production by appropriately stimulated mouse and/or guinea-pig peritoneal exudate macrophages was variably inhibited by supernatants from some tumour cells and some normal cells. Changes in these biochemical activities of macrophages do not appear to be closely related to the anti-inflammatory activity of tumour cell products.
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PMID:Effects of tumour cell culture supernatants on some biochemical activities of macrophages. 689 96


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