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:3.5.1.52 (PNGase F)
1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IgD receptors on murine T cells have been reported in this issue [Tamma, S. M. L., Amin, A. R., Finkelman, F. D., Chen, Y.-W., Thorbecke, G. J. & Coico, R. F. (1991) Proc. Natl. Acad. Sci. USA 88, 9233-9237] to bind either the first or third constant region of the heavy-chain of IgD molecules--findings that could not be satisfactorily explained by IgD amino acid sequences. We now find that boiled IgD molecules or low-Mr fragments from protease-digested IgD still inhibit binding of IgD-coated erythrocytes to IgD receptors. This inhibitory activity can be absorbed with the murine IgD-binding lectin from Griffonia simplicifolia 1 (GS-1) immobilized on Sepharose. N-linked glycans, obtained from N-glycanase-treated IgD and purified by binding to GS-1-Sepharose, also inhibit rosette formation of T-helper cells bearing receptors for IgD with IgD- or mutant IgD-coated erythrocytes. Deglycosylated IgD, produced by treatment with N-glycanase, no longer binds to the lectin and fails to inhibit IgD rosetting. Binding of intact IgD to T cells is also competitively inhibited by N-acetylgalactosamine, galactose, N-acetylglucosamine, and neoglycoproteins containing these sugars. These results clearly show that N-linked glycans, present in both the first and third constant regions of the delta heavy-chain domains, are prerequisites for binding of IgD to IgD receptors.
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PMID:Specificity of the murine IgD receptor on T cells is for N-linked glycans on IgD molecules. 192 87

Extracellular superoxide dismutase, EC-SOD, the main superoxide dismutase in biological fluids, is known from its lectin binding to be a glycoprotein. We have characterized the glycosylation of recombinant EC-SOD. A tryptic digest of the protein contained only one glycosylated peptide. This peptide was specifically bound to lectins and stained by periodic acid-Schiff stain. Although appearing very large on size-exclusion chromatography, it was shown to be glycosylated at only one site, asparagine-89, by specific cleavage with glycanases followed by mass spectrometry of the resulting peptide. Based on the binding properties of the peptide to concanavalin A and lentil lectin and the elution profile of N-glycanase-treated glycopeptide on ion-exchange chromatography, the carbohydrate appears to be the complex biantennary type with a core fucose.
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PMID:Glycosylation of extracellular superoxide dismutase studied by high-performance liquid chromatography and mass spectrometry. 193 27

Four isoforms of glycosylated prolactin (G-pPRL) were isolated from porcine pituitary glands by affinity chromatography and concanavalin A-Sepharose, based upon differences in their affinity for the lectin. Structural analysis indicated differences in the carbohydrate units of the four G-pPRLs. N-glycanase treatment cleaved the oligosaccharide from the G-pPRLs, establishing N-linked glycosylation. The binding of G-pPRLs to receptors from lactating rabbit mammary glands was only 3-8% that of nonglycosylated pPRL (NG-pPRL). The immunological crossreactivity of the G-pPRLs varied from 36 to 65% that of NG-pPRL. When tested in the pigeon crop sac bioassay, G-pPRLs were only 11-40% as active as NG-pPRL. The metabolic clearance rate of one of the G-pPRLs was slower and another faster than that of NG-pPRL. We conclude that there are several forms of G-PRL of variable immuno- and bio-potencies in the porcine pituitary, and that the current radioimmunoassay for the hormone does not measure the actual bioactivity.
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PMID:Isolation and biochemical properties of four forms of glycosylated porcine prolactin. 195 78

Receptor-mediated recognition and adhesion to laminin, a specific glycoprotein from basement membranes, exert an important role in many biological phenomena. Studying cell surface proteins of B16-F10, a metastatic murine melanoma cell line, we identified a 120-140 kDa glycoprotein (gp120/140) that binds laminin. This glycoprotein was recognized by a polyclonal antibody raised against the human fibronectin receptor beta 1-integrin chain, as well as immunoprecipitated by an anti-alpha 6 chain (monoclonal antibody GoH3), characterizing it as an alpha 6/beta 1-integrin. Its binding to laminin was specific and displayed moderate affinity, as its apparent dissociation constant was 18 nM. To characterize the influence of carbohydrate moieties on the laminin-gp120/140 interaction, metaperiodate oxidation, metabolic inhibition of glycosylation, and enzymatic deglycosylation studies were performed. Our results indicate that gp120/140 Asn-linked oligosaccharides play a part in this interaction. Reciprocally, both metaperiodate and N-glycanase treatment of native laminin reduced its binding to gp120/140, characterizing the latter as a lectin-like molecule. These results point to glycosylation processes as a possible mechanism for variable binding specificity profiles among integrins.
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PMID:Asn-linked oligosaccharide-dependent interaction between laminin and gp120/140. An alpha 6/beta 1 integrin. 199 8

The beta-subunit of human choriogonadotropin (hCG) has two complex type N-linked and four O-linked carbohydrate chains. To further evaluate the specificity of the carbohydrate moiety on the hCG function, we have expressed hCG beta subunit in the baculovirus insect cell system to modify its carbohydrate structures. The recombinant hCG beta (rhCG beta) was efficiently secreted in the medium and was purified to homogeneity by immunoaffinity chromatography using a highly specific monoclonal antibody against hCG beta. The homogeneity of the recombinant subunit was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis performed under reducing and nonreducing conditions and reverse phase high performance liquid chromatography. rhCG beta had molecular weights of 22,500 and 33,000 under reducing and nonreducing conditions, respectively. Digestion with N-glycanase cleaved the Mr = 22,500 protein to 18,000, while digestion with Endo H or Endo F yielded an additional protein band of 20,500 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The carbohydrate analysis by pulse amperometry yielded the relative number of 2.5, 2.4, 3.7, and 11.3 residues of fucose, N-acetylgalactosamine, galactose, and mannose, respectively, based on a value of 4 residues for N-acetylglucosamine. Lectin binding studies showed rhCG beta to bind with concanavalin A with a high affinity and not with wheat germ agglutinin. In the studies with endoglycosidases together with the carbohydrate analysis and lectin binding properties, rhCG beta appears to have two high mannose-type N-linked and three to four O-linked carbohydrate simple disaccharide chains. The carbohydrate modification of the beta-subunit did not alter its immunopotency and its ability to combine with hCG alpha. The reconstituted hormone made up of rhCG beta and hCG alpha was found to be similar to hCG in biological properties such as receptor binding and in its ability to stimulate cAMP and steroidogenesis.
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PMID:Carbohydrate variant of the recombinant beta-subunit of human choriogonadotropin expressed in baculovirus expression system. 199 3

Rubella virus contains two envelope glycoproteins, E1 and E2. The amino acid sequence for both glycoproteins is known, as is the number of N-glycosylation sites. This study has demonstrated the presence of O-linked carbohydrates bound to E2 and determined structural characteristics of the N-linked oligosaccharide chains. O-linked sugars were found to be resistant to digestion with N-glycanase but sensitive to beta-elimination with alkaline borohydride. After treatment with neuraminidase, O-linked sugars bound to peanut agglutinin, suggesting the presence of the disaccharide galactose-N-acetylgalactosamine, masked by sialic acid. The N-linked oligosaccharides were large, probably four-branched, and showed a lectin binding pattern suggesting the complex type, with terminal Gal, GlcNAc and sialic acid. No Endo H-sensitive carbohydrates were detected.
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PMID:Characterization of carbohydrates linked to rubella virus glycoprotein E2. 201 96

We previously described the production of monoclonal antibodies against a preparation of membrane glycoproteins from human brain [Berglund et al. (1987) J. Neurochem. 48, 809-815]. One of the glycoproteins, recognized by monoclonal antibody CF3, was specifically expressed in the brain. We now report the isolation and characterization of this glycoprotein, called glycoprotein 135 (Gp135). Gp135 was purified by means of lentil lectin affinity chromatography and immunoaffinity chromatography, using monoclonal antibody CF3, from a crude membrane extract of human brain cortex. Gp135 was shown to consist of a glycosylated single polypeptide chain with an apparent molecular mass of 135 kDa. The size of the polypeptide moiety was estimated to 115 kDa following N-glycanase digestion. The glycoprotein is anchored in the membrane by a glycosylphosphatidylinositol tail, as shown by phospholipase C digestion and liposome incorporation experiments. Amino acid sequence analysis of the amino terminal, and of an internal peptide obtained by V8 protease digestion of the glycoprotein, revealed a strong similarity to three previously described glycoproteins from chicken (contactin and F11) and mouse (F3) brains. These glycoproteins belong to the immunoglobulin superfamily and are implicated in cell adhesion phenomena in the developing brain. Gp135 may be the human counterpart to one or several of these glycoproteins.
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PMID:Isolation and characterization of a membrane glycoprotein from human brain with sequence similarities to cell adhesion proteins from chicken and mouse. 202 73

In this study we report that bone and platelet osteonectin are structurally and functionally heterogeneous in terms of glycosylation and collagen binding capacity. The relative sensitivity of bone and platelet osteonectin to specific glycosidases was used to evaluate potential differences in glycosylation. Although native bone and platelet osteonectin are electrophoretically nonidentical, N-glycanase treatment yielded products with the same apparent molecular weight. Bone osteonectin was also susceptible to cleavage by endo H but not to neuraminidase, while platelet osteonectin was susceptible to neuraminidase but not to endo H. In lectin blotting experiments of bone and platelet osteonectin, concanavalin A bound specifically to bone osteonectin but not to platelet osteonectin. However, Lens culinaris agglutinin bound to platelet osteonectin but not to bone osteonectin. These data suggest that bone and platelet osteonectin differ in their oligosaccharide side chain structures, with bone osteonectin possessing a high mannose-type and platelet osteonectin, a complex-type structure. Solid-phase binding techniques were used to functionally evaluate bone and platelet osteonectin in terms of collagen binding. Although bone osteonectin bound specifically to types I, III, and V collagen, platelet osteonectin had no apparent affinity for these collagen types suggesting that the two proteins are also functionally distinct.
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PMID:The collagen binding specificity of bone and platelet osteonectin is related to differences in glycosylation. 203 56

The cytoplasmic tubulovesicular and canalicular membranes of gastric parietal cells are intimately involved in hydrochloric acid secretion. To characterise the glycoproteins of these membranes, we examined a panel of lectins for reactivity with parietal cells in paraffin sections of rat, dog and pig stomach. The poly-N-acetyllactosamine-specific lectin from Lycopersicon esculentum (tomato) and from Solanum tuberosum (potato), and the galactose-specific lectin Ricinus communis agglutinin (RCA120), showed strong cytoplasmic binding of parietal cells of all three species, with a pattern indicative of an intracellular membrane network. Binding to parietal cells was confirmed by double-labelling studies with parietal cell auto-antibodies from patients with autoimmune gastritis. Mucous cells and mucin also bound these lectins strongly. Other gastric cell types did not stain with either tomato or potato lectin, but stained weakly with RCA120. Electron-microscopic examination of lectin binding sites using biotinylated tomato lectin or RCA120 and streptavidin-gold, revealed specific binding to the luminal face of parietal cell tubulovesicular and canalicular membranes as well as the contents of mucous cell secretory granules. Tomato lectin and RCA120 reacted by lectin blotting with a major species of apparent molecular weight 60-90 X 10(3) Mr from rat, dog and pig gastric membranes. A tubulovesicular membrane fraction, enriched 10-fold for K(+)-dependent phosphatase activity, was also enriched three-fold for tomato lectin binding as assessed by a solid-phase lectin assay. The 60-90K (K = 10(3) Mr) component, in 125I-labelled detergent extracts of dog tubulovesicular membranes, bound to an affinity support of tomato lectin-Sepharose and was specifically eluted with N,N',N'-triacetylchitotriose. Digestion with N-glycanase collapsed the 60-90K component into a sharp 35K band. We conclude that: (1) a 60-90K membrane glycoprotein localised on the luminal face of tubulovesicles and canaliculi of parietal cells interacts strongly with tomato lectin and RCA120; and (2) the glycoprotein is composed of a 35K core protein glycosylated with N-glycans probably containing poly-N-acetyllactosamine sequences with terminal galactosyl residues. The properties of this 60-90K glycoprotein are identical to a major parietal cell autoantigen recognised by sera of patients with autoimmune gastritis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Poly-N-acetyllactosamine-specific tomato lectin interacts with gastric parietal cells. Identification of a tomato-lectin binding 60-90 X 10(3) Mr membrane glycoprotein of tubulovesicles. 216 41

The high Mr glycoprotein (gp300) of equine herpesvirus type 1 was found to have an Mr, estimated by SDS-PAGE, of over 400,000 and was confirmed as being a surface glycoprotein by 125I-labelling. In contrast to [3H]glucosamine, gp300 showed very low levels of [3H]glucosamine, gp300 showed very low levels of [3H]mannose incorporation. The Mr of gp300 showed no detectable change upon treatment of purified virus with N-glycanase, and showed only a small change in virus-infected cells treated with tunicamycin. In addition, gp300 failed to bind the lectin concanavalin A. Taken together, these results indicate a lack of N-linked carbohydrate on gp300. The major carbohydrate species were found to be composed primarily of O-linked chains, as indicated by the sensitivity of the protein to monensin, to exoglycanase enzymes specific for sugars present in O-linked chains and to mild alkaline borohydride treatment, which revealed three species of carbohydrate of Mr of greater than 10,000, 2400 and 1100, respectively. Neuraminidase treatment and binding of Helix pomatia lectin indicated the presence of alpha-N-acetylglucosamine and sialic acid as terminal sugars. Immunological cross-reactivity of gp300 with a high Mr protein of equine herpesvirus type 4 was shown and it also exhibited a marked Mr variation in the vaccine strain Rhinomune.
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PMID:Characterization of the high Mr glycoprotein (gP300) of equine herpesvirus type 1 as a novel glycoprotein with extensive O-linked carbohydrate. 217 54


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