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 effects of several antioxidants on the three major functions of human neutrophils--oxidative burst, secretion and leukotriene formation--were investigated with special emphasis on the lipophilicity. The most striking differences were obtained when ascorbate and the lipophilic ester ascorbyl palmitate were compared. As expected, the luminol- and lucigenin-dependent chemiluminescence was inhibited by all antioxidants to a different degree. Ascorbyl palmitate was able to block the biphasic luminol-dependent response completely with IC50 values of 10 and 25 microM for the first and second phase, respectively. In contrast, ascorbate only blocked efficiently the first phase of the response. The secretion of elastase was inhibited by ascorbyl palmitate dose-dependently with an IC50 value of around 200 microM, whereas ascorbate was completely inactive. Electron microscopy supported the assumption that inhibition was due to a block in degranulation and not to enzyme inactivation. This was further supported by a parallel, although somewhat lower, inhibition of other secretory enzymes like myeloperoxidase, beta-glucuronidase or lysozyme. Cells treated with the Ca2+-ionophore A23187 responded by LTB4-synthesis which was also inhibited by ascorbyl palmitate. A very efficient inhibition was observed in cell homogenates with an IC50 value of 1.5 microM. No inhibition by ascorbate was detected in both systems. Concomitant with the inhibition of 5-lipoxygenase the activity of 15-lipoxygenase increased. We conclude that cellular reductants may control neutrophil functions and that the inhibition by ascorbyl palmitate of the three processes relevant for inflammatory responses could be of therapeutic importance.
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PMID:The suppression of granulocyte functions by lipophilic antioxidants. 283 72

A skin window technique was used to study the morphology of leucocytes in upper dermis and exudate during nickel challenge in patients with contact allergy to nickel. Contact allergic patients and healthy volunteers tested with a skin widow without addition of nickel to the chamber medium served as controls. The morphology of the leucocytes in dermis was studied in biopsies taken 8, 24, or 48 h after skin window application, and in a parallel test the morphology of the exudate was examined by sequential collection of the chamber medium during a 48 h period. The infiltrate in dermis of contact allergic patients with nickel challenge in the chamber medium showed a time-dependent increase of mononuclear cells, eosinophils and basophils and a concomitant decrease of polymorphonuclear granulocytes, characteristic of a combined specific and unspecific inflammation. The morphology of the exudate in contact allergic patients exposed to nickel showed a dominance of polymorphonuclear granulocytes throughout the study period, while mononuclear cells, eosinophils and basophils were detected at a much lower quantity and with a considerable delay. Further, we studied the kinetics of the leucocyte granule proteins: lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate fluid in a parallel test. A significant higher flux was found for all during the second day of allergen exposure compared to contact allergic patients without allergen challenge as well as normal volunteers. The increased protein fluxes were not accompanied by an increased flux of polymorphonuclear granulocytes in the exudate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate in delayed type hypersensitivity. 283 74

The effect of the antimalarial drug mefloquine on human neutrophil degranulation, chemiluminescence, superoxide production and viability was examined in vitro. Mefloquine was found to significantly stimulate the release of lysozyme, beta-glucuronidase and myeloperoxide at a concentration of 10 micrograms/ml (2.5 X 10(-5) M) without loss of cell viability. At 40 micrograms/ml mefloquine (1 X 10(-4) M) cell viability was significantly decreased. Mefloquine at 10 micrograms/ml also significantly increased the release of lysozyme and beta-glucuronidase but not myeloperoxidase when neutrophils were stimulated with opsonized zymosan. At a lower zymosan concentration myeloperoxidase release was also increased. Enzyme activity was not directly stimulated by mefloquine. Mefloquine at 10 micrograms/ml significantly increased luminol-dependent chemiluminescence but significantly inhibited lucigenin-dependent chemiluminescence when neutrophils were stimulated with opsonized zymosan. Under these conditions superoxide release, measured by cytochrome c reduction, was inhibited to a lesser degree. These results are discussed with reference to our previous report that mefloquine inhibits the neutrophil iodination reaction [Immunology 58: 125-130, 1986] and the use of mefloquine as an anti-inflammatory drug.
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PMID:Stimulation of human neutrophil degranulation by mefloquine. 284 64

Because it has recently been hypothesized that human milk is antiinflammatory, the effects of aqueous human colostrum on human polymorphonuclear leukocyte (PMN) respiratory burst activity and selected enzymatic activities was examined. Aqueous colostrum was found to spontaneously reduce ferricytochrome C in a concentration-dependent manner, prohibiting use of the standard assay to measure superoxide production. It also caused a significant concentration-dependent prolongation of the lagtime from stimulation of PMN with phorbol myristate acetate to the appearance of hydrogen peroxide. Substitution of an enzymatic peroxide-generating system for PMN did not alter the effect of colostrum. Colostrum also suppressed myeloperoxidase activity and lysozyme activity, but not beta-glucuronidase activity in PMN lysates. Inclusion of colostrum in an in vitro assay of PMN-mediated cell detachment significantly suppressed this PMN-mediated effect. These data demonstrate that aqueous human colostrum significantly interferes with PMN oxygen metabolic and enzymatic activities that are important in the mediation of acute inflammation.
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PMID:Antioxidant properties of human colostrum. 284 22

Rat neutrophils added to 3H-labelled glomerular basement membrane (GBM) treated with rabbit anti-rat GBM antiserum degraded the GBM as judged by the release of 3H-labelled peptides. Cells from female animals promoted a more marked degradation than cells from males. This correlated with measurements of higher levels of elastase in granule fractions from the cells. The subcellular distributions of granule marker enzymes was found not to differ between the sexes. Levels of myeloperoxidase, lysozyme, cathepsin G, alkaline phosphatase, gamma-glutamyltranspeptidase and N-acetyl-beta-glucosaminidase showed no sex-based differences. No alpha-mannosidase could be detected in the cells.
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PMID:Biochemical studies of neutrophils from male and female rats: a differential response to basement membrane treated with nephrotoxic antiserum. 284 4

The enzyme system composed of human neutrophilic myeloperoxidase (H2O2-oxidoreductase, EC 1.11.1.7), H2O2 and Cl-, at pH 4.5 interacts with egg white lysozyme (EC 3.2.1.17) in several stages. In the first stage, occurring at lysozyme to H2O2 molar ratio of 1:1.4-1.8, the lysozyme loses its enzyme activity but does not yield any derivative distinguishable from the native protein on polyacrylamide gel electrophoresis (PAGE). The second stage of oxidation begins at lysozyme to H2O2 molar ratio above 1:5, producing a change in the lysozyme spectrum at 260-290 nm, and yielding protein derivatives with molecular masses equal to multiples of 14.3 kDa, i.e. the lysozyme molecular mass. This implies that an excessive oxidation of lysozyme by the myeloperoxidase-H2O2-Cl- system produces cross-linking of lysozyme molecules to di-, tri-, tetra-, and pentameric structures. At lysozyme to H2O2 molar ratio exceeding 1:12 a water insoluble white product, which consists of a set of lysozyme cross-linked derivatives, is obtained.
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PMID:Action of myeloperoxidase-hydrogen peroxide-chloride system on the egg white lysozyme. 285 92

In this report, we have presented our experience with a patient with a rare cutaneous granulocytic sarcoma. In addition to hematoxylin and eosin, myeloperoxidase stain and specific stains for lysozyme and esterase were helpful in confirming the histologic diagnosis of granulocytic sarcoma. Despite multiple attempts to control this patient's tumor by conservative surgery, radiation therapy, and chemotherapy, we eventually had to resort to limb amputation. This procedure restored a meaningful quality of life to this patient for one and a half years prior to the development of acute leukemia. Treatment with corticosteroids at the time of surgery may have prevented a local recurrence of granulocytic sarcoma despite positive tissue margins. Our experience underscores the importance of directing treatment toward the granulocytic sarcoma whereas the myelodysplasia concurrently present may not require therapy for several years.
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PMID:Treatment of cutaneous granulocytic sarcoma in a patient with myelodysplasia. 292 35

Two mouse monoclonal antibodies, L12.2 and S5.22, were developed that are specific for human neutrophilic granulocytes and produce a twofold to threefold stimulation of n-formyl-methionine-leucyl-phenylalanine (FMLP)-induced chemotaxis. Stimulation of chemotaxis by the antibodies is specific for FMLP and is concentration dependent. L12.2 appears to be more potent in stimulating chemotaxis and is isotypically distinct from S5.22. In addition, although L12.2 reacts only with mature peripheral blood granulocytes, S5.22 reacts with leukemic cells of both myeloid and monocytic origin and with immature granulocyte precursor cells. This suggests that L12.2 interacts with an antigen that appears late in the differentiation pathway, whereas S5.22 binds to an antigen that is present throughout the myeloid lineage. By means of the under-agarose and Boyden chamber techniques, L12.2, but not S5.22, by itself was also found to be a potent granulocyte chemoattractant. Cells in a gradient of L12.2 display polarized and oriented morphology. L12.2 alone, but not S5.22, also stimulates granulocyte phagocytosis and induces superoxide anion production. Neither L12.2 nor S5.22 affected the release of myeloperoxidase or lysozyme from granulocytes either alone or in combination with FMLP, C5a, or the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). These results suggest that L12.2 interacts with a single antigenic determinant on granulocytes that is involved in chemotaxis, phagocytosis, and superoxide anion release.
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PMID:Stimulation of human neutrophilic granulocyte chemotaxis by monoclonal antibodies. 298 Dec 60

Propionibacterium acnes, the target of inflammation in acne, was tested for its sensitivity to the bactericidal and degradative functions of human polymorphonuclear leukocytes (PMN), monocytes, and their fractions. P. acnes strains were not killed by PMN under any conditions and were variably killed by monocytes in the presence of serum from acne patients. Control strains of Staphylococcus aureus and Micrococcus lysodeicticus were susceptible to both PMN and monocyte killing. P. acnes strains were also not killed by lysozyme, chymotrypsin, H2O2, human serum, PMN granule lysate, and PMN and monocyte cell lysates. The organism was sensitive to the bactericidal activity of myeloperoxidase in acid pH. In addition, P. acnes was shown to be relatively resistant to the degradative action of PMN and monocyte lysates, whereas M. lysodeicticus, S. aureus, and Staphylococcus epidermidis were all degraded to various degrees. The moieties that were liberated from P. acnes by PMN enzymes were predominantly low in molecular weight (1,000 to 25,000) and were consistent with cell wall fragments.
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PMID:Susceptibility of Propionibacterium acnes to killing and degradation by human neutrophils and monocytes in vitro. 298 78

Elevated activities of beta-D-glucuronidase, myeloperoxidase, and lysozyme were found in polymorphonuclear leukocytes (PMNs) of both hypopituitary dwarfs and normal subjects after the administration of growth hormone (GH), as compared to the activities in PMNs from blood drawn immediately before the administration of GH. During in vitro incubation, GH was able to inhibit the release of lysosomal enzymes from resting PMNs. This inhibition may be one of the reasons for the elevated lysosomal enzyme activities observed in PMNs after the administration of GH. GH can also affect hexose monophosphate shunt (HMPS) activity and superoxide production by PMNs. The activity of HMPS is stimulated by GH in resting PMNs, while in PMNs incubated with zymosan the GH inhibits both HMPS and superoxide production.
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PMID:Effect of growth hormone on the activity of some lysosomal enzymes in neutrophilic polymorphonuclear leukocytes of hypopituitary dwarfs. 299 87


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