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:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antibacterial activity of a myeloperoxidase (MPO)-glucose oxidase system was found to be greatly increased by granulocyte elastase, present in azurophil granules of human neutrophils. The MPO-H2O3-mediated killing of both Escherichia coli and Staphylococcus aureus was potentiated by granuocyte elastase at an acid pH, whereas at pH 7.4 only killing of E. coli was potentiated. The potentiating effect of elastase was not dependent on the enzymatic properties of the protein since it was not abolished by heating, which destroys the enzymatic activity. A peptide chloromethyl ketone elastase inhibitor abolished both elastolytic activity and the pctentiating effects on MPO-H2-O2-mediated bacterial killing. The antibacterial activity of chymotrypsin-like cationic protein of human neutrophils was also potentiated by elastase. Other degradative enzymes isolated from human granulocytes, e.g., collagenase and lysozyme, did not potentiate MPO-H2O2-mediated or cationic protein-dependent bacterial killing. The present study indicates that a neutrophil constitutent, elastase, which is not microbicidal by itself, can initiate sublethal changes that render some microorganisms more susceptible to the action of microbicidal agents like MPO and chymotrypsin-like cationic protein.
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PMID:Microbicidal mechanisms of human granulocytes: synergistic effects of granulocyte elastase and myeloperoxidase or chymotrypsin-like cationic protein. 1 11

We used immunofluorescent microscopy to characterize the abnormal granules in neutrophils from five patients with Chediak-Higashi disease. Monospecific antiserums to the azurophilic markers myeloperoxidase, elastase, cathepsin G and lysozyme, and to the specific granule markers lactoferrin and lysozyme, were labeled with fluorescein and rhodamine and were used to demonstrate two antigens in the same cell simultaneously. The abnormal granules in Chediak-Higashi neutrophils contained both azurophilic and specific granule markers. Normal-appearing lactoferrin-positive granules were also present, but normal azurophilic granules were not seen. Analysis of bone-marrow samples from two of these patients suggested that the abnormal granules were formed during granulocyte maturation by the progressive aggregation and fusion of normally formed azurophilic and specific granules. These results are consistent with a membrane abnormality or a defect of microtubular function leading to inappropriate granule fusion, and suggest that the granular abnormality is more generalized than previously appreciated.
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PMID:Immunocytochemical identification of azurophilic and specific granule markers in the giant granules of Chediak-Higashi neutrophils. 7 4

The subcellular localization of granulocyte collagenase, elastase and chymotrypsin-like cationic protein was determined using velocity centrifugation of cytoplasmic granules of human polymorphonuclear leukocytes. The proteases were assayed by immunochemical and enzymatic methods. Measurements of lactoferrin and myeloperoxidase distinguish exactly between constituents of specific and azurophil granules. Collagenase, elastase and chymotrypsin-like cationic proteins showed an almost identical sharp and unimodal distribution. They co-sedimented with myeloperoxidase demonstrating that these enzymes are localized exclusively in the azurophil granules.
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PMID:Localization of chymotrypsin-like cationic protein, collagenase and elastase in azurophil granules of human neutrophilic polymorphonuclear leukocytes. 19 54

Human granulocytes release 25-30% of the granular neutral proteases, collagenase and elastase, to the exterior of the cell during phagocytosis of yeast cells or immune complexes. Similar amounts of myeloperoxidase and lactoferrin are released. Crossed immunoelectrophoresis demonstrated that collagenase and elastase released extracellularly formed complexes with serum alpha1-antitrypsin. The presence of alpha1-antitrypsin complexes with granulocyte collagenase and elastase were also demonstrated in inflammatory processes, e.g. in the peritoneal exudate of acute peritonitis. The reactivity of neutrophil proteases with natural plasma protease inhibitors must be considered in assessing the role of these proteases as the etiologic agent of tissue damage and degradation during the inflammatory process.
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PMID:The extracellular release of granulocyte collagenase and elastase during phagocytosis and inflammatory processes. 19 89

Human polymorphonuclear leukocytes (PMN) phagocytosing opsonized antigen-antibody complexes, produce dialyzable species of activated oxygen which are capable of partially suppressing the elastase-inhibiting capacity (EIC) of whole human serum or purified human alpha1-proteinase inhibitor. Serum EIC was partially protially protected by superoxide dismutase, catalase, or mannitol, suggesting that hydroxyl radical, formed by interaction of superoxide radical and hydrogen peroxide, might be responsible for this effect. NaN3 also partly protected EIC, implicating myeloperoxidase-mediated reactions as well. An artificial superoxide rradical-generating system, involving xanthine and xanthine-oxidase, could be substituted for phagocytosing PMN with resultant EIC suppression. These results are consistent with previous demonstrations of the release of potent oxidants by stimulated PMN, as well as earlier studies from our laboratory showing sensitivity of alpha1-proteinase inhibitor to inactivation by oxidants. Oxidative inactivation of proteinase inhibitors in the microenvironment of PMN accumulating at sites of inflammation may allow proteases released from these cells to more readily damage adjacent connective tissue structures.
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PMID:In vitro suppression of serum elastase-inhibitory capacity by reactive oxygen species generated by phagocytosing polymorphonuclear leukocytes. 22 Feb 83

The concentrations of several polymorphonuclear neutrophilic lysosomal constituents were quantitated by immunochemical and enzymatic assays in 28 inflammatory and 9 noninflammatory synovial fluids. The quantities of lactoferrin, myeloperoxidase, and enzymatically determined lysozyme were covariate with the neutrophil count. Enzymatic activities measured with synthetic substrates developed for the assay of chymotryptic-like cationic protein (cathepsin G) and elastase, along with immunochemically determined lysozyme, were independent of the neutrophil count. Although the latter assays were developed and standardized with human neutrophilic lysosomal constituents, they measure different activities in inflammatory synovial effusions. No elastase was detected if elastin was used as the substrate. Regardless of the source of the enzymes, there was a negative correlation between their concentration and the degree of radiographic destruction of the joint from which the fluid was obtained. Lysosomal enzymes in solution in synovial fluid are not likely to be primarily involved in cartilage destruction.
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PMID:Lysosomal enzymes in inflammatory synovial effusions. 22 41

1. Biopsies of rectal mucosa were obtained for histology and enzyme analysis from 32 patients with inflammatory and functional bowel disorders, and the biopsies were classified morphologically as active colitis, quiescent colitis or normal. 2. Supernatant fractions of biopsy homogenates were assayed for their content of the proteolytic enzymes alpha-chymotrypsin, elastase and cathepsin D, and of protein, unsaturated vitamin B12-binding capacity, lysozyme, myeloperoxidase and N-acetyl-beta-glucosaminidase. 3. Mean unsaturated vitamin B12-binding capacity was significantly raised above normal in the active colitic mucosa, and mean lysozyme activity was raised above normal in both active and quiescent mucosae. 4. In active colitic mucosa there was no rise above normal in mean activities of any of the proteolytic enzymes, though a significant fall below normal occurred in mean N-acetyl-beta-glucosaminidase activity in the active colitic group.
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PMID:Mucosal enzymes in human inflammatory bowel disease with reference to neutrophil granulocytes as mediators of tissue injury. 22 86

Polymorphonuclear leukocytes (PMNs) are one of the main sources of enzymes responsible for tissue damage in inflammatory processes. These enzymes are stored in two types of cytoplasmic granules. Azurophil granules contain lysosomal hydrolases, neutral serine proteinases, and bactericidal elements (myeloperoxidase and lysozyme). Specific granules contain collagenase, lysozyme and lactoferrin but lack lysosomal hydrolases. PMNs store all four classes of tissue proteinases, carboxyl, thiol and serine proteinases in the azurophil granules, and metallo proteinases in the specific granules. Three serine proteinases have been identified, elastase, cathepsin G and a third enzyme, which together account for a large proportion of the protein of the azurophil granules. In the course of phagocytic events, all these enzymes are released extracellularly. The neutral proteinases degrade proteoglycans and collagen. In vitro, they stimulate B-lymphocytes, which suggests that they may have immuno-potentiating activity when they are released at sites of chronic inflammation.
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PMID:The polymorphonuclear leukocyte. 34 82

High titer, monospecific antibodies to human granulocyte myeloperoxidase, cathepsin G, elastase, lysozyme, and lactoferrin were conjugated with fluorescein and rhodamine and used for immunofluorescent staining of mature neutrophils obtained from 25 patients with acute and chronic leukemia. In 11 (44%) of the patients, two populations of mature neutrophils were detected. The abnormal cells were identified by complete deficiency of one or more markers and constituted 10%-100% of the total number of neutrophils. This immunocytochemical approach may permit recognition of mature cells derived from leukemic clones, and serial determinations of the ratio of normal to abnormal cells may be useful in the management of patients with leukemia.
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PMID:Immunocytochemical identification of abnormal polymorphonuclear neutrophils in patients with leukemia. 40 Aug 91

Antineutrophil cytoplasmic autoantibodies (ANCA) react with proteins found in the granules of neutrophils and the peroxidase-positive lysosomes of monocytes, including myeloperoxidase (MPO), proteinase 3 (PR-3), and elastase. ANCA-associated diseases, such as Wegener's granulomatosis and polyarteritis nodosa, are characterized by necrotizing vascular inflammation. The inflammatory lesions typically contain both neutrophils and mononuclear phagocytes, with the latter sometimes predominating, for example, in the granulomatous lesions of Wegener's granulomatosis. We investigated the presence of the ANCA target antigens PR3, MPO, and elastase in mononuclear phagocyte cytoplasm during the course of differentiation in vitro and in alveolar and peritoneal macrophages. We observed that ANCA antigens were down-regulated during mononuclear phagocyte differentiation, with the loss corresponding to that of peroxidase-positive granules. This suggests that ANCA can directly interact only with monocytes and early exudative macrophages and not with mature macrophages.
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PMID:Reactivity of antineutrophil cytoplasmic autoantibodies with mononuclear phagocytes. 131 Oct 14


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