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)

Binding sites for prolactin were identified in a plasma-membrane-enriched fraction isolated from livers of mature female rats. 125I-labelled sheep prolactin prepared by the lactoperoxidase procedure retained the same molecular integrity and binding affinity as the native hormone at physiological pH. The receptors bound prolactin from different species, whereas non-lactogenic hormones were not bound. The binding of 125I-labelled sheep prolactin was activated equally by bivalent and univalent cations, bivalent cations exerting their maximal effect at much lower concentrations. The association of 125I-labelled sheep prolactin with the receptor was a time- and temperature-dependent process. Partial dissociation was detected. The binding of 125I-labelled sheep prolactin was strongly influenced by pH, with an optimum observed at pH 6.5. Receptor activity was destroyed by Pronase and phospholipase C, whereas neuraminidase increased binding. Treatment of the membranes by ribonuclease and deoxyribonuclease did not affect the binding. Binding of 125I-labelled sheep prolactin was inhibited by p-chloromercuribenzoic acid, dithiothreitol and by brief exposure to high temperatures. Scatchard analysis of the binding of 125I-labelled sheep prolactin to receptors indicated that prolactin has a high affinity for its receptor. Binding of prolactin to liver membranes showed some properties different from those observed with mammary cells. Binding by these tissues differed in pH optimum, in effects of ions, and in response to neuraminidase.
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PMID:Characterization of prolactin binding by membrane preparations from rat liver. 3 84

Biochemical characterization of serologically detected human melanoma antigens was undertaken for the development of immunodiagnostic assays in melanoma. An antiserum from a human melanoma patient, which detected melanoma antigens expressed on a large proportion of different melanoma cells, was used in leucocyte-dependent cytotoxic antibody (LDA) 51Cr-release assays to monitor the purification of melanoma antigens in urea/acetate extracts of lactoperoxidase 125I-labelled melanoma cell membranes. The separation procedures included affinity chromatography on Concanavalin A, gel filtration on porous polyacrylamide beads and preparative isoelectric focusing. The fractions were also monitored by polyacrylamide electrophoresis in sodium dodecyl sulphate and by measurement of beta 2 microglobulin and carcinoembryonic antigen content. The antigens detected by this antiserum appeared to be acidic (pI 3.5) low-mol.-wt glycoproteins of approximately 15,000 daltons which were resistant to heating at 56 degrees C and digestion with neuraminidase, but susceptible to repeated freeze-thawing and trypsin digestion. They did not appear to be related to HLA antigens, beta 2 microglobulin or known foetal antigens. The nature of the antigens detected in these studies is as yet unknown, but they appear similar to those described in the sera and urine of melanoma patients in previous reports. Thes combined results and the frequent expression of these antigens on melanoma cells from different patients suggest that assays to detect this antigen may provide a valuable immunodiagnostic aid in the management of melanoma.
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PMID:Detection of a low-molecular-weight antigen on melanoma cells by a human antiserum in leukocyte-dependent antibody assays. 9 79

The usefulness of a lectin, Limulus polyphemus agglutinin (LPA) has been tested in a series of mammalian tissues with sialic acid-containing glycoproteins. In nearly all the tissues employed, the positive peroxidase-labelled LPA diaminobenzidine (LPA-PO-DAB) reaction of various histological structures was markedly diminished in intensity or abolished, following digestion with neuraminidase. In the same tissues, sialic acid added with LPA-PO abolished the LPA-PO-DAB reaction or notably suppressed its intensity. In the majority of the tissues tested, the LPA-PO-DAB-Alcian Blue (AB) (pH 1.0 or 2.5) procedures appear to be useful dual staining methods which enable one to colour selectively sialic acid-containing and other acidic carbohydrates. In view of the endogenous peroxidase activity in particular histological structures, however, appropriate control staining procedures should be performed when the LPA-PO-DAB procedure is employed, either alone or in combination with AB procedures, to determine the histochemical properties of sialic acid-containing glycoproteins.
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PMID:The use of peroxidase-labelled Limulus polyphemus agglutinin for the histochemistry of sialic acid-containing glycoproteins in light microscopy. 9 94

Immune complexes of horseradish peroxidase (HRP) and rabbit IgG antibodies to HRP were used to study the Fcgamma receptors in normal human placenta. Cryostat sections of placental tissue were incubated with the complexes, and the peroxidase activity was revealed histochemically. The bound complexes were localized to the apical surface of the trophoblasts and endothelial cells of the fetal stem vessels. Binding also occurred within the wall of some fetal vessels, to stromal cells and occasionally to areas corresponding to the trophoblastic membrane. The strongest binding was obtained with immune complexes prepared at slight antigen excess. Eight- to sixteen-fold increased concentration of human and rabbit IgG was needed to block the binding of immune complexes. Bovine and porcine IgG did not block the binding. Treatment of tissue sections with neuraminidase enhanced the binding activity of the receptors. The technique is very convenient for studies of Fcgamma receptors in tissue. However, unfixed frozen placental tissue was not suitable for ultrastructural studies.
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PMID:The placental Fcgamma receptors studied using immune complexes of peroxidase. 10 Aug 70

The fat body lobes of Galleria mellonella are surrounded by basement membrane - a fine granular layer of connective tissue. This membrane has an affinity for ruthernium red. The results obtained after treatment of the fat body with neuraminidase, hyaluronidase, phospholipase C and proteolytic enzymes suggest that glycoproteins and phospholipoproteins are constituents of this basement membrane. The basement membrane also has the ability to bind concanavalin A-peroxidase, which is associated with the presence of mannoside residues.
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PMID:The ultrastructure and ultracytochemistry of the basement membrane of the Galleria mellonella fat body. 13 74

The effects of bacterial neuraminidase on production of hydrogen peroxide (H2O2) and killing of Staphylococcus aureus by human polymorphonuclear leukocytes (PMN) were studied. The concentration of H2O2 was measured by the disappearance of scopoletin fluorescence in the presence of horseradish peroxidase. The results indicated that desialylation of human PMN inhibited the stimulation of H2O2 production during phagocytosis. It also markedly impaired the killing of S. aureus. Impaired killing of S. aureus by desialylated PMN was due to impaired intracellular killing rather than defective phagocytosis.
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PMID:Hydrogen peroxide production and killing of Staphylococcus aureus by human polymorphonuclear leukocytes. 18 59

Adsorption of u.v.-inactivated Sendai virus on to NIL8 hamster cells causes fusion of the cells into polykaryocytes within 2 h. "Infected" cells were incubated at 37 degrees C for periods of 10 min to 8 h and their surface proteins iodinated with [125I] catalysed by peroxidase. Structural components of the viral envelope, such as haemagglutin-neuraminidase (HN) and probably also the fusion protein (F) were detected in the cell membrane for periods up to 4 h post infection.
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PMID:The fate of protein subunits of parainfluenza (Sendai) virus after adsorption to NIL8 hamster embryo cells. 21 28

The topography of the external surface of the Balb/c mouse erythrocyte has been investigated and compared to the human erythrocyte by using a series of protein radiolabeling probes. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the pattern of Coomassie Blue stained proteins was very similar for mouse and human erythrocyte ghosts, as was the distribution of radioactivity in protein bands after lactoperoxidase catalyzed radioiodination. The mouse erythrocyte glycoproteins identified by periodic-acid-Schiff and 'Stains-All' reagents, sialic acid analysis of gel slices, binding of 125I-wheat germ agglutinin and 125I-concanavalin A to the gels, and glycoprotein radiolabeling techniques, differed markedly from the sets of proteins labeled by radioiodination, and also differed from the human erythrocyte glycoproteins. Instead of the PAS I to PAS IV series of sialoglycoproteins characteristic of human erythrocytes, the mouse erythrocyte possesses a broad band of sialoglycoproteins with several peaks ranging in mol wt from 65,000 to 32,000. The same group of sialoglycoproteins were labeled by the periodate/B3H4-technique specific for terminal sialic acid, and the galactose oxidase/B3H4-method (plus neuraminidase) specific for galactosyl/N-acetylgalactosaminyl residues penultimate to sialic acid. These results emphasize the necessity to employ a variety of protein radiolabeling probes based on different labeling specificities, to study the membrane topography of cells which are poorly understood compared to the human erythrocyte membrane.
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PMID:Identification of differences between the surface proteins and glycoproteins of normal mouse (Balb/c) and human erythrocytes. 22 11

The Fc-receptor of normal human leukocytes, of CLL-cells, and of hematopoietic cell lines was demonstrated with soluble peroxidase-anti-peroxidase (PAP) complexes. In about 9% of normal lymphocytes an almost continuous, strong labeling of the cell membrane was established. Some of these lymphocytes were characterized by a peculiar uniform fine structure. The percentage of PAP-labeled monocytes was in the range of 25%, neutrophils nearly 100%, eosinophils 0%, CLL-cells 10%. Labeled portions of the membrane were interiorized from monocytes. The lymphoid cell-line Daudi established from a Burkitt's lymphoma appeared almost negative, the cell line K562 established from a myeloid leukemia in 75% of the cells strongly positive. PAP-labeling was not influenced by preincubation with trypsine or with neuraminidase; it was negative when PAP-F(ab)2 was used. Results of PAP-labeling were not always in agreement with EA-rosettes or with agg-Ig.
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PMID:Demonstration of the Fc-receptor of blood cells by soluble peroxidase-anti-peroxidase (PAP) complexes. 35 Mar 18

The sialic acid composition and the display of cell surface sialyl components of several metastatic variant RNA-virus-transformed non-producer BALB/c 3T3 have been studied in culture. The following observations have been made concerning the sialyl components in these lines: (1) the compositions of whole-cell total, protein-bound and lipid-bound sialic acid were not appreciably different; (2) the surface sialic acid studied using the neuraminidase-galactose oxidase method and metabolic labelling followed by neuraminidase hydrolysis showed a positive correlation with the metastatic properties of these lines; (3) the degree of surface sialylation determined by galactose oxidase--sodium borotritide labelling of neuraminidase-treated and untreated cells revealed that 44--89% of exposed galactose and/or N-acetyl galactosamine residues of total cell-surface saccharides were sialylated in highly and intermediately metastatic lines as compared with 11-30% in the poorly and non-metastatic lines; (4) the cell surface glycoproteins and glycosphingolipids contributed equally well in their degree of sialylation and there was a positive correlation with the metastatic properties of the cells in vivo; (5) the cell surface proteins labelled by the lactoperoxidase-catalyzed iodination technique, followed by gel electrophoresis, showed some minor differences between metastatic variant lines. However, glycoproteins detected by the galactose oxidase labelling of neuraminidase-treated and untreated cells showed major differences in composition between the metastatic variant lines. The study of four highly metastatic lines has shown that the cells of these lines were enriched in several sialyl-glycoproteins, whereas three non tumorigenic lines and two poorly metastatic or non-metastatic lines contained unsialylated glycoproteins. The results indicate an enhancement of the degree of sialylation of surface glycoconjugates accompanying the metastatic process in RNA-virus-transformed mouse lines.
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PMID:Cell surface sialylation of glycoproteins and glycosphingolipids in cultured metastatic variant RNA-virus transformed non-producer BALB/c 3T3 cell lines. 38 11


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