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)

A panel of monoclonal antibodies, including a reagent designated ERIC-1, have been characterized as binding to the human neural cell adhesion molecule (NCAM). These monoclonal antibodies bind in a relatively uniform manner to a variety of normal and neoplastic tissues arising from the neuroectoderm. However, multiple forms of the protein are known to arise from the differential splicing of exons within the NCAM gene located on chromosome 11 at q23. On human adult brain, four isoforms of 180, 170, 145 and 120 kDa have been identified. Here, we report the identification of another NCAM isoform of 95 kDa that is apparent on tissues following either N-glycanase or neuraminidase treatment to remove carbohydrate and sialic acid residues from the molecule respectively. NCAM expression is further complicated by differential post-translational modification of the molecule which is developmentally regulated. In general, fetal NCAM is more heavily polysialylated than the adult forms of the molecule. Human fetal brain has been shown to express the heavily sialylated embryonic form of NCAM, but following neuraminidase digestion, a similar pattern of NCAM expression is seen to that in adult brain. A variety of human brain tumours examined also show different patterns of NCAM expression, despite their uniform staining with monoclonal antibodies. The significance of these observations for designing new molecular and immunological approaches to the diagnosis of a variety of primary tumours is reviewed.
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PMID:Expression of alternative isoforms of the neural cell adhesion molecule (NCAM) on normal brain and a variety of brain tumours. 189 Oct 65

A novel platelet glycoprotein has been purified and characterized. This glycoprotein, designated Pltgp40, is an acidic sialylated 40,000-dalton protein that bears both O-linked and N-linked oligosaccharides. Treatment of Pltgp40 with neuraminidase resulted in a 5,000-dalton reduction in its Mr and a 1.5 Unit alkaline shift in the isoelectric point, indicating the presence of a large number of sialic acid residues. A similar size reduction and change in pl were observed after treatment of Pltgp40 with O-glycanase showing that sialic acids are present on O-linked oligosaccharides. Digestion of Pltgp40 with N-glycanase reduced the Mr to approximately 20,000 daltons but did not affect the isoelectric point, suggesting that Pltgp40 contains six to seven nonsialylated N-linked carbohydrate chains. High Mr proteins were observed in affinity purified Pltgp40 and were identified as detergent-stable protein oligomers consisting of multiple 40,000-dalton monomers. Immunodepletion and direct binding studies indicated that Pltgp40 was not equivalent to Ig Fc receptor type II, another 40,000-dalton glycoprotein expressed on platelets. However, Pltgp40 copurified with Fc receptor type II when platelet extracts were loaded onto human IgG affinity columns, raising the possibility that Pltgp40 may associate with Fc receptors or Fc receptor-lg complexes. Amino acid sequence analysis of the N-terminus of Pltgp40 was performed and confirmed that Pltgp40 is a novel platelet glycoprotein. Epitopes on Pltgp40 appear to be widely expressed because monoclonal antibodies against Pltgp40 also reacted with a variety of myeloid, lymphoid, and epithelial cells. Pltgp40 was detected on activated but not resting platelets, indicating that Pltgp40 is a platelet activation marker.
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PMID:Characterization of a novel self-associating Mr 40,000 platelet glycoprotein. 174 15

We isolated 7.4 mg of pure renin from 2 kg of rat kidneys using affinity chromatography on pepstatin-aminohexyl-Sepharose and an octapeptide renin inhibitor, H-77-Sepharose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that renin consists of two polypeptide chains linked by a disulfide bond, one of Mr = 36,000 (heavy chain) and the other of Mr = 3,000 (light chain). The amino-terminal 10-amino acid sequences of the heavy and the light chains were identical to the sequences beginning at Ser72 and Asp355, respectively, of the amino acid sequence of preprorenin deduced from the renin cDNA sequence. Amino acid sequencing of the carboxyl-terminal peptide of the heavy chain, generated by digestion with lysyl endopeptidase, showed that the carboxyl-terminal residue of the heavy chain is Phe. Thus, the propeptide of prorenin is cleaved after Thr71, followed by removal of two amino acids, Arg353 and Asn354, the result being formation of the heavy and light chains. Thus, the site of cleavage of rat prorenin is after a nonbasic amino acid, in contrast to the cleavage of the propeptide after a pair of basic amino acids in mouse submaxillary renin, human renal renin, and many secretory proteins. Treatment of renin with neuraminidase or glycopeptidase F had no apparent effect on the charge heterogeneity of renin. Glycosylation probably does not contribute to charge heterogeneity.
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PMID:Amino-terminal amino acid sequence and heterogeneity in glycosylation of rat renal renin. 201 14

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

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 dopamine transporter from rat caudate-putamen was photolabeled with [125I]DEEP as previously described. Treatment of photolabeled membranes with neuraminidase and N-glycanase reduced the molecular weight of the [125I]DEEP photolabeled dopamine transporter complex, whereas treatment with alpha-mannosidase had no effect. The solubilized [125I]DEEP photolabeled dopamine transporter complex readily bound to wheat-germ agglutinin but not to concanavalin-A sepharose columns. These results suggest that the carbohydrate moiety of the dopamine transporter is N-linked and contains significant quantities of sialic acid but not high mannose residues. A DEEP binding protein was readily detectable in other brain regions including the nucleus accumbens and olfactory tubercle, but not in the prefrontal cortex, olfactory bulb or hypothalamus under similar conditions. The DEEP binding protein in the other brain regions was similar to that in the striatum.
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PMID:Dopamine transporter: deglycosylation with exo- and endoglycosidases. 205

Two-dimensional gel electrophoresis (2DGE) and image processing were used to quantify protein and carbohydrate heterogeneity in human plasma fibronectin (FN) and its enzymatically produced domains. After a 30 minute thermolysin digest of FN, the domains were identified in 2DGE by their known isoelectric points and molecular weights, which were compared to domain standards purified by hydroxyapatite, gel exclusion and heparin-Sepharose chromatography. Three individual species were observed in the cell binding domain which may correspond to the heterogeneity known to result from alternative splicings of the fibronectin gene. In addition, the carbohydrate heterogeneity in the gelatin binding domain was analyzed by 2DGE and isoelectric focusing (IEF) before and after treatment with N-glycanase and neuraminidase to remove selected carbohydrate moieties. Five individual species which differ in carbohydrate structure were observed. The results also indicate a carbohydrate dependent stabilization of the gelatin binding domain with respect to proteolytic digestion.
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PMID:Separation and characterization of fibronectin domains by two-dimensional electrophoresis. 209 3

Mo3 is an activation Ag expressed by human monocytic cells after stimulation in vitro by PMA, LPS, certain cytokines, and muramyl dipeptide. The structural characterization of Mo3 has been made possible by the development of a mAb (anti-Mo3f) that immunoprecipitates Mo3 from Nonidet P-40 lysates of radiolabeled PMA-stimulated U-937 cells and LPS-activated monocytes. On SDS-PAGE (nonreducing conditions) of anti-Mo3f immunoprecipitates, U-937 Mo3 is a single broad band of 39 to 66 kDa, whereas monocyte Mo3 is smaller with an apparent molecular mass of 32 to 56 kDa. Under reducing conditions, there is an increase in the m.w. of both species of Mo3 suggesting the existence of internal disulfide bonds. Mo3 is a glycoprotein with carbohydrate of the N-linked complex type as evidence by a reduction in m.w. by 40 to 50% after treatment with endoglycosidase F or N-glycanase; neuraminidase treatment produces a 3-kDa reduction in m.w. Deglycosylated Mo3 isolated from U-937 and monocytes have similar m.w. suggesting that the molecular heterogeneity of the native Mo3 may be due to differences in glycosylation. Mo3 is sensitive to phosphatidylinositol-specific phospholipase C with the release of native Mo3 from the surface of PMA-stimulated U-937 cells. These results indicate that Mo3 is a member of the glycosylphosphatidylinositol-linked family of surface glycoproteins.
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PMID:A structural characterization of the Mo3 activation antigen expressed on the plasma membrane of human mononuclear phagocytes. 213 44

This paper describes a large-scale purification procedure of the amiloride binding component of the epithelium Na+ channel. [3H]Phenamil was used as a labeled ligand to follow the purification. The first two steps are identical with those previously described [Barbry, P., Chassande, O., Vigne, P., Frelin, C., Ellory, C., Cragoe, E. J., Jr., & Lazdunski, M. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 4836-4840]. A third step was a hydroxyapatite column. The purified material consisted of a homodimer of two 88-kDa proteins that migrated anomalously in SDS-PAGE to give an apparent Mr of 105,000. Deglycosylation by treatment with neuraminidase and endoglycosidase F or with neuraminidase and glycopeptidase F indicated that less than 5% of the mass of the native receptor was carbohydrate. Sedimentation analysis of the purified Na+ channel in H2O and D2O sucrose gradients and gel filtration experiments led to an estimated molecular weight of the [3H]phenamil receptor protein-detergent-phospholipid complex of 288,000 and of the native [3H]phenamil receptor protein of 158,000. [3H]Br-benzamil is another labeled derivative of amiloride that recognized binding sites that had the same pharmacological properties as [3H]phenamil binding sites and that copurified with them. Upon irradiation of kidney membranes, [3H]Br-benzamil incorporated specifically into a 185-kDa polypeptide chain under nonreducing electrophoretic conditions and a 105-kDa protein under reducing conditions. The same labeling pattern was observed at the different steps of the purification. Reconstitution of the purified phenamil receptor into large unilamellar vesicles was carried out. A low but significant phenamil- and amiloride-sensitive electrogenic Na+ transport was observed.
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PMID:[3H]phenamil binding protein of the renal epithelium Na+ channel. Purification, affinity labeling, and functional reconstitution. 216 Feb 71

Bovine plasma protein C inhibitor was purified; it was then characterized in comparison with human protein C inhibitor. The specific inhibitory activity of the purified inhibitor for bovine activated protein C was 8,500 times that of the inhibitor in plasma. The purified inhibitor showed a single band with Mr 56,000 by SDS-PAGE at pH 7.0, and two bands at pH 8.8, a major one with Mr 56,000 and a minor one with Mr 105,000, under both unreduced and reduced conditions. The pI range of the inhibitor was between 4.4 and 6.1. The Mr of the inhibitor was reduced by treatment with neuraminidase, O-glycanase, and also with glycopeptidase-A, suggesting that the inhibitor has both Asn-linked and Ser/Thr-linked carbohydrate chains. Twenty-seven of the NH2-terminal 49 amino acid residues of the bovine inhibitor, which lacks the first 4 residues from the NH2-terminal amino acid sequence of human inhibitor, were identical to those of the human inhibitor. The bovine inhibitor inhibited bovine and human activated protein C, human thrombin, Factor Xa, Factor XIa, and plasma kallikrein with Ki = 1.0, 5.2, 2.6, 3.0, 1.3 X 10(-8) M, and 4.5 X 10(-9) M, respectively. The inhibitory rates for activated protein C and thrombin were accelerated significantly in the presence of heparin or negatively charged dextran sulfate. However, the acceleration by heparin or dextran sulfate for the inhibition of Factor Xa, Factor XIa, and plasma kallikrein was not significant. The bovine inhibitor did not inhibit human Factor XIIa or plasmin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Bovine plasma protein C inhibitor with structural and functional homologous properties to human plasma protein C inhibitor. 216 Apr 49


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