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)

A polar, nonpenetrating compound of high specific activity, diazotized (125I)-diiodosulfanilic acid (DD125ISA), has been developed as a label for exposed proteins of the human platelet plasma membrane, and platelet proteins and the pattern of labeling have been studied with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). That DD125ISA binds specifically to membrane proteins was demonstrated by: (1) the specific activity of isolated membrane protein was five to seven times that of whole platelet protein and (2) no proteins of intact platelets were labeled which were not represented in the isolated plasma membrane. That the DD125ISA-labeled membrane proteins were exposed on the cell surface was demonstrated by: (1) DD125ISA-labeled proteins were altered by trypsin treatment of intact, labeled platelets and (2) the pattern of labeling produced by reaction of isolated membranes with DD125ISA was quite different from that produced by the labeling of intact platelets. Analysis of platelet membrane proteins by SDS-PAGE demonstrated the glycoproteins previously described at 150,000 daltons (termed glycoprotein I) and 92,000 daltons (glycoprotein III) but we could discriminate two apparently distinct glycoproteins in the intermediate region (IIa: 125,000 daltons, and II: 118,000 daltons). Glycoproteins I and III were constant whereas IIa was clearly visible only in unreduced samples and II was predominant in reduced samples. Reaction of DD125ISA with intact platelets resulted in equal labeling of three of these four membrane glycoproteins (IIa, II, and III). The pattern of exposed proteins on the platelet surface labeled by DD125ISA was different from lactoperoxidase-131I, which labeled predominantly the 92,000 dalton glycoprotein, as demonstrated by simultaneous SDS-PAGE analysis. Therefore three glycoproteins of the human platelet plasma membrane are exposed to a radioisotope probe on the platelet surface and are accessible for contact interactions.
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PMID:Studies on platelet plasma membranes. I. Characterization of surface proteins of human platelets labeled with diazotized (125i)-diiodosulfanilic acid. 6 Apr 57

Chicken anti-human IgD antiserum (anti-delta) has demonstrated an antigenically cross-reactive homologue on rat lymphocytes. IgD and IgM are the only cell surface immunoglobulins detectable by the lactoperoxidase radiolabeling technique employed. The results indicate that, although rat surface IgD is antigenically distinct from rat IgM, the respective H chains co-electrophorese in 10% polyacrylamide-SDS gels. Rat delta-chain has an apparent m.w. of 73,000 daltons and exhibits a minor 65,000 dalton component which probably represents a partially degraded delta-chain. The ontogenic emergence of rat IgD occurs approximately 3.5 weeks after birth whereas IgM, in contrast, is apparent by 6 days of age. Thus, as in the human, IgM develops before IgD. IgD receptors are undetectable in the thymus but are present in increasing levels in spleen, blood, lymph nodes, and Peyer's patches.
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PMID:Structure and biologic functions of human IgD. XI. Identification and ontogeny of a rat lymphocyte immunoglobulin having antigenic cross-reactivity with human IgD. 6 67

A cell hybrid has been selected from fusion of a mouse myeloma and rat spleen cells immunized against mouse lymphoma cells that produces monoclonal antibody against the mouse lymphocyte surface glycoprotein, T200. Antibody binding assays employing the monoclonal antibody show that there are about 50,000-100,000 molecules of T200 glycoprotein on mouse thymocytes and that similar antigens are present on spleen and bone marrow but not detected on nonlymphoid tissues. Examination of the labeled molecules precipitated from detergent extracts of spleen cells and thymocytes iodinated by the lactoperoxidase technique by SDS-PAGE confirm that there are structural differences between the antigens found on B and T lymphocytes. The B-cell glycoprotein consists of at least one component of apparent mol wt 220,000 on SDS-PAGE, while the T-cell glycoprotein has an apparent mol wt of about 190,000.
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PMID:Interspecies spleen-myeloma hybrid producing monoclonal antibodies against mouse lymphocyte surface glycoprotein, T200. 7 61

Horseradish peroxidase was conjugated to immunoglobulin G via glutaraldehyde by a two-step procedure using an increasing excess of peroxidase in the second step reaction. The yield of conjugated monomeric IgG and the amount of free IgG were analyzed by SDS-polyacrylamide electrophoresis and gel-filtration. The antigen binding capacity of the enzyme-antibody conjugates was evaluated by radial immunodiffusion. Conjugation of peroxidase to IgG with a 1:20 molar:molar excess of glutaraldehyde-activated peroxidase resulted in a high yield of conjugated IgG without any detectable amounts of polymers of IgG or residual free IgG. The antigen binding capacity of the conjugate varied between different antigen-antibody systems, but in general it was not significantly different from that of native IgG. The enzyme activity was reduced to 70% of the activity of native peroxidase.
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PMID:Studies on the conjugation of horseradish peroxidase to immunoglobulin G via glutaraldehyde. 11 93

The protein and glycoprotein composition of Kirsten murine leukaemia-sarcoma virus (KiMSV(KiMuLV) was studied using SDS-polyacrylamide gel electrophoresis. Twenty-three polypeptides and three glycoproteins were detected following electrophoresis by staining with Coomassie blue and PAS or by autoradiography of isotopically labelled virus. Protein components were assigned positions in the virus particle, envelope, nucleoid or intermediate area based on iodination with lactoperoxidase and sedimentation in potassium citrate equilibrium gradients. The KiMSV (KiMuLV) envelope contained 11 polypeptides and three glycoproteins. The virus nucleoid and intermediate area were each composed of six proteins. The protein composition of KiMSV(KiMuLV) was highly reproducible when virus was harvested from cells of the same subcluture generation. However, the protein profiles were altered with repeated in vitro passages of the virus-producing cell line.
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PMID:Proteins of Kirsten murine leukaemia-sarcoma virus: localization within the virus particle by iodination and fractionation techniques. 16 14

A double antibody radioimmunoassay for human ApoA-II is reported. ApoA-II isolated from human plasma high density lipoprotein (HDL) by column chromatography migrated as a single band on polyacrylamide disc gel electrophoresis, had the appropriate amino acid composition, and provoked the production of monospecific antisera. (125)I-ApoA-II (iodinated by lactoperoxidase, purified by Sephadex G-75 chromatography) migrated with "cold" ApoA-II as a single band on disc gel electrophoresis in SDS. Its specific radioactivity was 5-12 mCi/ micro g. In assays, (0.05 M barbital buffer, 0.01% Triton X-100, pH 8.6) over 90% of (125)I-ApoA-II was bound by excess first antibody and over 95% was displaced by excess "cold" ApoA-II. Low density lipoprotein, very low density lipoprotein, ApoA-I, ApoC-II, and ApoC-III displaced no counts. Intraassay and interassay coefficients of variation for lipoprotein or plasma samples were 7 +/- 4 and 11 +/- 6%, respectively. As little as 1.0 ng of ApoA-II was detectable with a precision of 10%. ApoA-II made up 20-25% of the proteins of HDL (d 1.083-1.19), HDL(2) (d 1.083-1.124), and HDL(3) (d 1.124-1.19) on column chromatography. The ApoA-II contents of these HDL fractions were also 20-25% by radioimmunoassay. Similar results were obtained whether assays were carried out on intact or delipidated HDL samples. Thus, in contrast with ApoA-I (only 10% of which is detectable), all of the ApoA-II contents of intact HDL are detected with accuracy by this assay. Plasma levels of ApoA-II in young normolipemic subjects were approximately 40 mg/dl (n = 29). In these subjects, over 98% of ApoA-II was found in the d 1.063-1.21 density fractions.
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PMID:Apolipoprotein A-II content of human plasma high density lipoproteins measured by radioimmunoassay. 19 5

We have analyzed the surfacr proteins of cultured normal rat kidney (NRK) cells and virus-transformed NRK cells subjected to iron deprivation. Such a treatment specifically induces two transformation-sensitive plasma membrane-associated glycoproteins with a subunit molecular weight of 160,000 (160 K) and 130,000 (130 K) daltons in NRK cells. In these cells the 160 K glycoprotein is readily available to lactoperoxidase-mediated iodination, and the 130 K is apparently inaccessible to iodination. Major differences were revealed when iodinated membrane proteins of normal and virus-transformed cells subjected to iron deprivation were compared. In Kirsten sarcoma virus-transformed NRK cells the 160 K glycoprotein was weakly labeled. In two clones of simian virus 40-transformed NRK cells the 160 K glycoprotein was weakly labeled or not at all. The 130 K glycoprotein was inaccessible to iodination in all virus-transformed cell lines. The 160 K and 130 K glycoproteins were isolated from plasma membranes of NRK cells using preparative SDS gel electrophoresis. Antibodies generated against these glycoproteins stained the external surfaces of NRK cells and induced antigen redistribution. Evidence presented suggests that 160 K and 130 K are plasma membrane-associated procollagen molecules. A possible interaction of these proteins with transferrin is also described. The data suggest that these proteins may have an important role in the sequence of events leading to transformation.
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PMID:Isolation and immunological characterization of an iron-regulated, transformation-sensitive cell surface protein of normal rat kidney cells. 23 20

The mouse myeloid leukemia cell line (M1) is known to differentiate in vitro into macrophages and granulocytes upon treatment with various inducers including mouse ascitic fluid. Changes of cell surface proteins during differentiation of M1 cells were analyzed by the lactoperoxidase-catalyzed radioiodination method and SDS-polyacrylamide slab gel electrophoresis. Treatment of the cells with ascitic fluid changed the electrophoretic pattern of the iodinated proteins, the prominent change being the appearance of a new protein with a molecular weight of 180 000 (P180). Iodinated P180 was also detected in normal macrophages in granulocytes, which are similar to differentiated M1 cells. This protein was metabolically labeled with L-[14C]fucose, increasing with the period of the treatment. P180 was not expressed on ascitic fluid-treatment of a resistant clone of M1 cells that could not be induced to differentiate. These results indicate that P180 is a glycoprotein that is exposed on the outer surface of differentiated M1 cells, and that its expression is associated with differentiation of the cells. P180 was solubilized from 125I-labeled macrophages with detergents bound to concanavalin A-Sepharose. This suggests that P180 is one of the receptors for concanavalin A. Therefore, P180 may contribute partly to the increases in agglutinability by concanavalin A and in the number of concanavalin A binding sites on the surface of M1 cells, which are known to be associated with differentiation of M1 cells.
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PMID:Differentiation-associated changes in membrane proteins of mouse myeloid leukemia cells. 29 Mar 96

Immunological and chemical studies of cell surfaces from normal and transformed BALB/c fibroblasts have shown alterations associated with transformation. The cells studied include normal lines which do not cause tumors when injected into BALB/c mice, viral transformants, and spontaneous transformants which cause tumors that either regress or grow progressively, killing the host. The spontaneously transformed progressors include cell lines which are immunogenic and nonimmunogenic as determined by the ability of tumor excision to protect an animal from subsequent rechallenge by tumor cells. Tumor-bearing mice produce lymphocytes which are nonspecifically cytotoxic for all the normal and transformed lines. Some of the cell lines induce specific antibody formation in BALB/hosts. Antisera have been prepared in rabbits which are specific for the transformed cell lines. These antisera can be used to determine specific surface changes on the transformed cells. Chemical studies have shown glycolipid alterations between the normal cells and some, but not all, of the transformants. Glycoproteins labeled by lactoperoxidase-125I or [3H] glucosamine were compared by SDS gel electrophoresis. Results from these studies do not show changes associated with malignancy. Individual glycoprotein regions from gels were treated with pronase, and the glycopeptides compared by Sephadex G50 chromatography. Alterations in glycopeptides from several cellular glycoproteins are the only changes which appear to be associated with malignancy.
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PMID:Chemical and immunological studies of cell surfaces from normal and transformed cells. 33 94

Mannose-binding hemagglutinins were found in the extracts of a pyocyanin-forming Pseudomonas aeruginosa, which contain galactose-specific hemagglutinins. They were purified simultaneously with the latter proteins by heating to 70 degrees C, precipitating with ammonium sulfate, application to a Sepharose 4B column, and elution from it by 0.05 M mannose. The mannose-specific hemagglutinins were shown to be similar to the galactophilic ones in (a) being glycoproteins of very low molecular weight (about 11 000 by SDS gel electrophoresis), (b) their tendency to aggregate, and (c) their ability to effect stronger agglutination of erythrocytes treated with papain than of untreated ones. They were found to resemble them also in their reaction with simple sugars and interactions with divalent cations, which are essential for their activity. In these properties, as well as in their relative resistance to heat and to proteolytic enzymes, these two types of bacterial hemagglutinins are like most of the plant, contrasted with the animal, hemagglutinins. The reactions with mannose and mannose-bearing compounds (yeast mannan, horseradish peroxidase (EC 1.11.1.7), and serum globulins), which are not shared with the galactophilic Pseudomonas hemagglutinins, indicate a relationship of the mannose-binding protein of Pseudomonas to the plant lectin concanavalin A. The mannose-binding hemagglutinins do not exhibit identical cell-agglutinating spectra owing to difference in profiles of sugar specificity and relative affinity to mannose derivatives compared with free mannose.
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PMID:Mannose-binding hemagglutinins in extracts of Pseudomonas aeruginosa. 40 63


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