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)

Antisera reactive with the Abelson murine leukemia virus (A-MuLV)-specified P120 (anti-AbT sera) were produced in C57L/J mice. Of many strains tested, only C57L/J reproducibly rejected syngenic A-MuLV-induced tumor cells; after multiple immunizations their sera would immunoprecipitate both P120 and Moloney-MuLV (M-MuLV) proteins. Using labeled A-MuLV-induced nonproducer cells, only P120 could be detected by anti-AbT sera, suggesting that it may be the only A-MuLV-specified protein. Reactivity of anti-AbT sera with P120 was not blocked by M-MuLV virion proteins, implying that the sera recognize a portion of P120 that is not homologous to any M-MuLV product. Anti-AbT sera stained the surface of live, A-MuLV-transformed nonproducer cells in a two-stage immunofluorescence assay, and such staining was not blocked by M-MuLV protein. Also, intact A-MuLV-transformed cells absorbed much of the reactivity of certain anti-AbT sera for P120. Thus a portion of P120 appears to be exposed on the surface of transformed cells. P120 lacks detectable carbohydrate, is not affected by endoglycosidase H, and cannot be labeled by lactoperoxidase-catalyzed iodination. Thus P120 is an unusual surface protein.
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PMID:Preparation of syngeneic tumor regressor serum reactive with the unique determinants of the Abelson murine leukemia virus-encoded P120 protein at the cell surface. 9 72

We have examined the properties of the alpha 5 beta 1 integrin of baby hamster kidney (BHK) cells, a ricin-resistant variant Ric14 lacking N-acetylglucosaminyl transferase I, and hence unable to complete assembly of hybrid- or complex-type N-glycans, and BHK cells treated with 1-deoxymannojirimycin (dMM), an inhibitor of Golgi mannosidases involved in the initial processing of N-glycan precursors. Comparable amounts of alpha 5 beta 1 integrin were isolated from these cells by chromatography of detergent extracts on a fibronectin cell-binding fragment affinity column and elution with EDTA. The alpha 5 beta 1 integrin obtained from normal BHK cells by fibronectin affinity chromatography contained mainly endoglycosidase H-resistant oligosaccharides, whereas in RicR14 cells or dMM-treated BHK cells these were entirely endoglycosidase H-sensitive. Analysis of lactoperoxidase labeled or long term biosynthetically 35S-labeled proteins from cultures of normal or glycosylation deficient cells showed similar steady state levels of alpha 5 beta 1 integrin and expression at the cell surface. Pulse-chase experiments in normal BHK cells showed rapid conversion of the alpha 5 subunit into a mature form containing oligosaccharides resistant to endoglycosidase H and slower maturation of a precursor beta 1 subunit, as in other cell types. In Ric14 cells the precursor beta 1 subunit was found to carry glycans larger than the fully processed Man5GlcNAc2 glycan of the mature subunit, indicating that the bulk precursor pool had not been translocated into the cis-Golgi compartment containing mannosidase I. We conclude that in BHK cells terminal oligosaccharide processing of alpha 5 beta 1 integrin subunits is not required for dimer formation, surface expression, and fibronectin binding, and that expression of the glycosylation defect of Ric14 cells on the alpha 5 beta 1 integrin does not account for the reduced adhesiveness of these cells on fibronectin compared with normal and dMM-treated BHK cells.
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PMID:Functional integrins from normal and glycosylation-deficient baby hamster kidney cells. Terminal processing of asparagine-linked oligosaccharides is not correlated with fibronectin-binding activity. 146 6

The specific phosphatase inhibitor okadaic acid (OA) induced fragmentation of the Golgi apparatus in interphase HeLa cells. Immunoelectron microscopy for galactosyltransferase identified a major Golgi fragment composed of a cluster of vesicles and tubules that was morphologically indistinguishable from the 'Golgi cluster' previously described in mitotic cells. The presence of homogeneous immunofluorescence staining for galactosyltransferase in OA-treated cells also suggested that isolated Golgi vesicles, previously found in mitotic cells, existed along with the clusters. After removal of OA, both clusters and vesicles appeared to participate in a reassembly pathway that strongly resembled that occurring during telophase. OA also induced inhibition of intracellular transport, another feature of mitotic cells. OA treatment prevented newly synthesised G protein of vesicular stomatitis virus (VSV) from acquiring resistance to endoglycosidase H and from arriving at the cell surface. In addition, fluid phase endocytosis of horseradish peroxidase (HRP) was reduced to less than 10% of control values. All these effects were dose-dependent and reversible. OA should be a useful tool to study the Golgi division and membrane traffic.
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PMID:Okadaic acid induces Golgi apparatus fragmentation and arrest of intracellular transport. 166 60

Mutant V.24.1 defines the End4 complementation group of temperature-sensitive Chinese hamster ovary cell mutants selected for resistance to protein toxins. We investigated the secretory pathway in the mutant cells and found: 1) The hemagglutinin of influenza virus failed to reach the plasma membrane and was retained in a form sensitive to endoglycosidase H at the restrictive temperature. 2) Transferrin receptors synthesized at the restrictive temperature remained sensitive to endoglycosidase H. 3) Secretion of total soluble protein into the medium was strongly reduced at high temperature. These data indicate that V.24.1 cells are defective in secretion at the restrictive temperature. To see what effect the lesion had on the endocytic pathway, we measured the accumulation and recycling of the fluid-phase marker horseradish peroxidase. Accumulation was inhibited by 50% while recycling was barely affected, suggesting that the rate of fluid-phase endocytosis was reduced. We previously showed that the clathrin-coated pit pathway of endocytosis was not affected in the mutant, indicated by a normal transferrin cycle (Colbaugh, P. A., Stookey, M., and Draper, R. K. (1989) J. Cell Biol. 108, 2211-2219). Thus, the secretory lesion correlates with reduced fluid-phase endocytosis without impairing the clathrin-dependent pathway of receptor-mediated endocytosis. We also investigated the delivery of endocytosed material to lysosomes and found that delivery was partially, but not completely, impaired in the mutant. This suggests that endocytosed material can enter lysosomes, although slowly, in the absence of a functional secretory pathway.
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PMID:Impaired secretion and fluid-phase endocytosis in the End4 mutant of Chinese hamster ovary cells. 212 70

The enzyme myeloperoxidase (MPO) is a functionally important glycoprotein of neutrophilic granulocytes and occurs in three major isoforms (forms 1, 2, and 3) that are dimeric structures composed of two heavy subunit-light subunit protomers, each of which is associated with a chlorine-like prosthetic group. In the present study, highly purified MPO isoforms were obtained from the cells of a single normal donor, and each protein was subjected to reductive alkylation under nondenaturing conditions. The resulting enzymatically active protomers were separated from unreacted dimer using gel filtration chromatography. Use of a fast protein liquid chromatography cation exchange system with a Mono S matrix revealed heterogeneity of the protomers, and allowed essentially complete resolution of the protomers of MPO form 2. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the two resolved protomeric species under reducing conditions revealed small but reproducible differences in the Mr of their heavy subunits (59,000 and 57,000). Treatment with either endo-beta-N-acetylglucosaminidase or peptide N-glycohydrolase F reduced the Mr of each heavy subunit by approximately 3000 but did not change their relative electrophoretic mobilities. Heavy and light subunits were prepared from each of the MPO isoforms by reductive alkylation under conditions that allowed full retention of the prosthetic group with the heavy subunit. Reverse-phase chromatography and amino-terminal sequencing showed that each MPO isoform contained one major species of light subunit and several minor species. No differences in peroxidatic activity or inhibition by salicylhydroxamic acid were observed among any of the MPO isoforms or resolved protomers, but the latter were considerably more heat labile than dimeric forms of the enzyme and a monomeric form isolated from HL-60 cells. This is the first report of the isolation and partial characterization of distinct protomers from a single isoform of human MPO and suggests that the structure of MPO is more complex than considered previously.
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PMID:Distinct chromatographic forms of human hemi-myeloperoxidase obtained by reductive cleavage of the dimeric enzyme. Evidence for subunit heterogeneity. 216 27

A rapid and convenient method was established for analysis of the N-linked carbohydrate chains of glycoproteins on nitrocellulose sheets. Proteins were separated by polyacrylamide gel electrophoresis, transferred to nitrocellulose sheets, reacted with peroxidase-coupled lectins, and detected by color development of the enzyme reaction. Four glycoproteins having N-linked oligosaccharide chains were used as test materials: Taka-amylase A (which has a high-mannose-type chain), ovalbumin (high-mannose-type chains and hybrid-type chains), transferrin (biantennary chains of complex type), and fetuin (triantennary chains of complex type and O-linked-type chains). Concanavalin A interacted with Taka-amylase A, transferrin, and ovalbumin but barely interacted with fetuin. After treatment of the glycoproteins on a nitrocellulose sheet with endo-beta-N-acetylglucosaminidase H, transferrin reacted with concanavalin A but Taka-amylase A and ovalbumin did not. Wheat germ agglutinin interacted with Taka-amylase A but not ovalbumin; therefore, they were distinguishable from each other. Fetuin and transferrin were detected by Ricinus communis agglutinin or peanut agglutinin after removal of sialic acid by treatment with neuraminidase or by weak-acid hydrolysis. Erythroagglutinating Phaseolus vulgaris agglutinin detected fetuin and transferrin. Thus, the combined use of these procedures distinguished the four different types of N-linked glycoproteins. This method was also applied to the analysis of membrane glycoproteins from sheep red blood cells. The terminally positioned sugars of sialic acid, alpha-fucose, alpha-galactose, and alpha-N-acetylgalactosamine were also detected with lectins from Limulus polyphemus, Lotus tetragonolobus, Maclura pomifera, and Dolichos biflorus, respectively.
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PMID:Analysis of N-linked oligosaccharide chains of glycoproteins on nitrocellulose sheets using lectin-peroxidase reagents. 241 Nov 64

Whole cell extracts of 10 clones of bloodstream forms of African trypanosomes representing two strains of Trypanosoma brucei gambiense, one strain of T. b. rhodesiense and one strain of T. b. brucei were fractionated on sodium dodecyl sulfate-polyacrylamide gels, electrophoretically transferred to nitrocellulose paper, and probed with horseradish peroxidase conjugated lectins to detect glycoproteins. Variant specific glycoproteins of all 10 clones bound peroxidase labeled concanavalin A, but peroxidase labeled wheat germ agglutinin bound to the variant specific glycoproteins of only 3 of the 10 clones examined. In addition, 22 other glycoproteins expressed in common by all clones bound peroxidase labeled concanavalin A; 19 common glycoproteins bound peroxidase labeled wheat germ agglutinin. Lectin binding to transferred glycoproteins was specifically inhibited by appropriate monosaccharides, alpha-methyl mannoside for concanavalin A and N-acetyl glucosamine for wheat germ agglutinin. Prior incubation of blots in endo-beta-N-acetylglucosaminidase H eliminated binding of peroxidase-labeled concanavalin A to most of the 22 common glycoproteins. Two glycoproteins, designated Gp 81 and Gp 110, were the major Endoglycosidase H resistant components. Endoglycosidase H treatment also reduced binding of peroxidase labeled concanavalin A to the variant specific glycoproteins of 7 clones. The variant specific glycoproteins from the 3 clones that bound peroxidase labeled concanavalin A following enzyme treatment were those that bound peroxidase labeled wheat germ agglutinin. These results show that African trypanosomes express a greater number of glycoproteins than has been reported previously and that only a limited number of these glycoproteins bear Endoglycosidase H resistant oligosaccharides.
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PMID:Trypanosoma brucei brucei, T. brucei gambiense, and T. brucei rhodesiense: common glycoproteins and glycoprotein oligosaccharide heterogeneity identified by lectin affinity blotting and endoglycosidase H treatment. 243 50

Gel electrophoresis, lectin affinity blotting, and endoglycosidase H digestion have been used to analyze the glycoprotein profiles of bloodstream and procyclic forms of Trypanosoma brucei brucei and T. b. gambiense. Proteins resolved by polyacrylamide gel electrophoresis were stained with silver nitrate or electrophoretically transferred to nitrocellulose and probed with a horseradish peroxidase conjugate of either concanavalin A or wheat germ agglutinin. Silver staining showed, as expected, that the expression of the variant specific glycoprotein was restricted to the bloodstream forms. Twenty-three concanavalin A binding proteins were resolved in blots of bloodstream forms. Concanavalin A binding molecules corresponding in electrophoretic mobility to 21 of these 23 bloodstream form glycoproteins were detected in blots of procyclic forms. The two concanavalin A binding glycoproteins present only in bloodstream form extracts were variant specific glycoprotein and an 81-kDa protein designated glycoprotein 81b. One concanavalin A binding molecule of 84 kDa, glycoprotein 84p, was detected only in procyclic forms. The 19 major wheat germ agglutinin binding glycoproteins expressed by bloodstream forms were not detected in procyclic forms; only small proteins or protein fragments in procyclic form extracts bound wheat germ agglutinin. Incubating transferred proteins in endoglycosidase H eliminated subsequent binding of concanavalin A to most of the 22 common glycoproteins of bloodstream forms. Three major concanavalin A binding glycoproteins of bloodstream forms, variant specific glycoprotein, glycoprotein 81b, and a 110-kDa molecule (glycoprotein 110b), and other minor glycoproteins carried sugar chains that resisted endoglycosidase H digestion. In contrast, concanavalin A did not bind to any procyclic form glycoproteins, including a 110-kDa concanavalin A binding molecule (glycoprotein 110p) after endoglycosidase H treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Trypanosoma brucei brucei and Trypanosoma brucei gambiense: stage specific differences in wheat germ agglutinin binding and in endoglycosidase H sensitivity of glycoprotein oligosaccharides. 244 Jul 11

The beta chain of human histocompatibility complex class II antigen, HLA-DR, showed 4 to 5 microheterogeneous spots on a gel obtained by two-dimensional polyacrylamide gel electrophoresis. The types of oligosaccharide chains on the beta chains were analyzed by the lectin-nitrocellulose sheet method for each microheterogeneous spot with 3 cell lines of two haplotypes (HLA-DR 4,4, and 3,3). Two kinds of oligosaccharide chains were observed and were essentially the same in the microheterogeneous spots from all three cell lines. One, the oligosaccharide chain on the most basic spot (beta 1), was stained with peroxidase-coupled concanavalin A (Con A-P.O.) but not with peroxidase-coupled wheat germ agglutinin and was sensitive to endo-beta-N-acetylglucosaminidase H (endo H), indicating that it was a high-mannose type. The oligosaccharide chains on other spots that were not stained with Con A-P.O. but were stained with peroxidase-coupled Ricinus communis agglutinin were resistant to endo H. beta 2 and beta 3 were stained with E-PHA. Thus, they probably had bisected biantennary and others probably had multiantennary complex-type oligosaccharides. Sialidase experiments showed that the charge heterogeneity was due to post-translational sialylation of the oligosaccharide chains. In pulse-chase experiments, the most basic spot of beta chain (beta 1) was labeled first, beta 2 and beta 3 were labeled next, and beta 4 was labeled last. These labeling characters accorded well with the results on the oligosaccharide types mentioned above.
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PMID:Microheterogeneity and oligosaccharide chains on the beta chains of HLA-DR, human major histocompatibility complex class II antigen, analyzed by the lectin-nitrocellulose sheet method. 251 91

Processing and localization of myeloperoxidase was studied in nonmyeloid cells. For this purpose BHK cells were transfected with human myeloperoxidase cDNA. In the transfected cells a protein with mol wt of 85,000 was found, which reacted with the specific anti-human myeloperoxidase antiserum. In size and in sensitivity to endo-beta-N-acetylglucosaminidase H this protein resembled the myeloperoxidase precursor synthesized in human promyelocytes. Unlike in the promyelocytes, in BHK cells the 85,000-Da protein was not converted to 60,000- and 14,000-Da polypeptides of the mature enzyme. In Percoll gradients the protein was found predominantly in the light membrane fractions. Microscopic examination revealed a conspicuous immune reaction over the endoplasmic reticulum and nuclear membranes and a moderate labeling over lysosome-like organelles. Pulse-chase experiments indicated that the protein was slowly released from the endoplasmic reticulum; after 1 day the protein was found in similar amounts in cells and in the medium. The secreted protein contained at least one endo-beta-N-acetylglucosaminidase-resistant oligosaccharide. It is suggested that normal intracellular segregation of myeloperoxidase depends on a signal or component, which is not or incompletely expressed in BHK cells.
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PMID:Synthesis and localization of myeloperoxidase protein in transfected BHK cells. 253 11


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