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)

Asparagine-linked oligosaccharides of stem bromelain glycopeptides were quantitatively released by digestion with the almond glycopeptidase which cleaves beta-aspartylglycosylamine linkage in glycopeptides with oligopeptide moieties. The primary structures of the two oligosaccharide components, (Man)3(Xyl)1(Fuc)1(GlcNAc)2 and (Man)2-(Xyl)1(Fuc)1(GlcNAc)2 were elucidated as Man alpha 1 leads to 6Man alpha 1 leads to 6[Xyl beta 1 leads to 2]Man beta 1 leads to 4GlcNAc beta 1 leads 4[Fuc alpha 1 leads to 3]GlcNAc and Man alpha 1 leads to 6[Xyl beta 1 leads to 2]Man beta 1 leads to 4 GlcNAc beta 1 leads to 4[Fuc alpha 1 leads to 3] GlcNAc, respectively.
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PMID:Complete structure of the carbohydrate moiety of stem bromelain. An application of the almond glycopeptidase for structural studies of glycopeptides. 50 Jun 6

A new type of glycopeptidase hydrolyzing beta-aspartylglycosylamine linkages was partially purified from almond emulsin by chromatography on Sephadex G-200 and DE 52. The enzyme degraded stem bromelain glycopeptide, Asn-Asn(Man3,Xyl1,Fuc1,GlcNAc2)-Glu-Ser-Ser, to yield equimolar amounts of intact oligosaccharide, peptide (Asn-Asp-Glu-Ser-Ser), and ammonia. The Km value for the stem bromelain glycopeptide was 4 mM, and the optimum pH was 5.2. The enzyme was markedly inhibited by 10 mM Cu2+, Fe3+, and Zn2+. Thiol inhibitors and actinomycete protease inhibitors had no effect. The glycopeptides used as substrates were prepared from stem bromelain, ovalbumin or ovotransferrin. The enzyme hydrolyzed glycopeptides with 3-11 amino acid residues, whereas it did not hydrolyze glycopeptides with 1-2 amino acid residues. Furthermore, Asn-oligosaccharide was not inhibitory to the enzyme.
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PMID:Some characteristics of a new glycopeptidase acting on aspartylglycosylamine linkages. 73 97

Oligosaccharides released enzymatically by N-glycanase from fetuin, alpha-acid glycoprotein, human chorionic gonadotropin, platelet-derived growth factor, and kallikrein were chromatographed on a polymeric pellicular anion-exchange column at pH values of 5 and 13. Separations occurred into groups of peaks containing the same number of sialic acids with an additional separation dependent upon the nature of the antennary structure present. High pH conditions were required for the optimum separation of fetuin oligosaccharides, while low pH conditions significantly improved resolution of oligosaccharides obtained from the other glycoproteins. The analytical separation of oligosaccharides under conditions of low pH has important implications in the development of chromatographic mapping and identification techniques for N-linked oligosaccharides present on recombinant proteins.
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PMID:High-performance anion-exchange chromatography of asparagine-linked oligosaccharides. 128 4

IgA receptors have been detected on monocytes, polymorphonuclear neutrophils (PMNs) and eosinophils, and on phagocytic cells at mucosal sites. These receptors bind both secretory and serum forms of immunoglobulin A (IgA) and require the Ca2 region of the IgA molecule for ligand recognition. Monocytes and PMNs modulate their expression of the IgA receptor upon treatment with cytokines, such as granulocyto-macrophage colony-stimulating factor, and lipopolysaccharide. Purified IgA receptors appear as heavily glycosylated molecules with an average molecular weight of 60 kD, dropping to 32 and 36 kD upon treatment with N-glycanase. The cDNA sequence encoding the IgA receptor has been determined by expression cloning, and predicts that the receptor consists of two Ig-like extracellular domaines, a transmembrane region and a cytoplasmic tail of 41 residues. Ligation of IgA receptors on phagocytic cells by multivalent IgA complexes induces a variety of responses, including superoxide generation, release of inflammatory mediators, phagocytosis, and killing of various pathogenic microorganisms. Thus the apparent role of these receptors is to amplify the protective effects of the IgA antibody, a function of potential importance to mucosal defense.
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PMID:Receptors for IgA on phagocytic cells. 128 21

An enzymatic procedure for the complete removal of the N-linked and O-linked oligosaccharide side chains of the sex steroid-binding proteins (SBP or SHBG) of human and rabbit plasma under native conditions is described. Deglycosylation was catalyzed by N-glycanase, neuraminidase, and O-glycanase and was monitored by SDS-PAGE, lectin blotting, and molecular weight analyses by electrospray mass spectrometry. Digestion of rabbit SBP with N-glycanase generated a major 39,777-Da protein and two minor ones of 39,389 and 39,545 Da. The molecular weight of the major protein agrees with the molecular weight calculated from the sequence of the sugar-free polypeptide monomer (39,769 Da: Griffin, P.R., Kumar, S., Shabanowitz, J., Charbonneau, H., Namkung, P.C., Walsh, K.A., Hunt, D.F., & Petra, P.H., 1989, J. Biol. Chem. 264, 19066-19075), whereas the other two are deglycosylated proteolytic cleavage products lacking the TQR and TQ sequences at the amino-terminus. The N- and O-linked side chains of human SBP were removed by sequential digestion with N-glycanase and neuraminidase/O-glycanase. A 38,771-Da protein was generated, which agrees well with the molecular weight of the sugar-free polypeptide monomer (Walsh, K.A., Titani, K., Kumar, S., Hayes, R., & Petra, P.H., 1986, Biochemistry 25, 7584-7590). N-deglycosylation of human and rabbit SBP has no effect on the steroid-binding activity, but removal of the O-linked side chains of N-deglycosylated human SBP results in an apparent 50% loss of steroid-binding activity and an increase in the Kd for the binding of 5 alpha-dihydrotestosterone from 0.3 mM to 0.9 nM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Complete enzymatic deglycosylation of native sex steroid-binding protein (SBP or SHBG) of human and rabbit plasma: effect on the steroid-binding activity. 130 75

A recombinant baculovirus (vAc-gB1) was constructed which expresses the glycoprotein B (gB) gene of herpes simplex virus type 1 (HSV-1). When Sf9 cells were infected with these recombinant viruses, a protein that was close in size to authentic HSV-1 gB was detected by gB polyclonal antibody. The recombinant gB was found on the membrane of Sf9 cells and was susceptible to tunicamycin, glycosidase F (PNGase F) and partially susceptible to Endo-H. Antibodies raised in mice to this recombinant recognized viral gB and neutralized the infectivity of HSV-1 in vitro. Mice inoculated with the recombinant gB were protected from lethal challenge with HSV-1.
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PMID:Expression of herpes simplex virus type 1 glycoprotein B in insect cells. Initial analysis of its biochemical and immunological properties. 131 Nov 36

The carbohydrate side chains of the thrombin-like serine protease ancrod from the venom of the Malayan pit viper Agkistrodon rhodostoma were liberated from tryptic glycopeptides by treatment with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and fractionated by high-performance liquid chromatography. Glycans obtained were characterized by digestion with exoglycosidases, methylation analysis and, in part, by liquid secondary-ion mass spectrometry and 1H-NMR spectroscopy. The results reveal that this snake venom glycoprotein contains partially truncated di-, tri- and tetraantennary complex type N-glycans carrying Fuc(alpha 1-6) residues at the innermost N-acetylglucosamine and solely (alpha 2-3)-linked sialic acid substituents. As a characteristic feature, ancrod oligosaccharides comprise mainly sialylated Gal beta 3GlcNAc beta lactosamine antennae. Furthermore, a small proportion of the sugar chains were found to carry a NeuAc alpha 3GalNAc beta 4GlcNAc beta antenna exclusively linked to C-2 of Man(alpha 1-3) residues of the pentasaccharide core. Thus, many of the glycans found represent novel glycoprotein-N-glycan structures.
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PMID:Carbohydrate structure of a thrombin-like serine protease from Agkistrodon rhodostoma. Structure elucidation of oligosaccharides by methylation analysis, liquid secondary-ion mass spectrometry and proton magnetic resonance. 131 84

The ligand-induced internalization of the hepatic glucagon receptor has been studied in rats in vivo using cell fractionation. Injection of glucagon (11 nmol/100 g BW) led to a 2- to 3-fold increase in glucagon-binding activity in Golgi-endosomal (GE) fractions along with a 10-20% decrease in binding activity in plasma membrane (PM) fractions. These changes were time and dose dependent, reaching a maximum by 12-24 min and undergoing reversal in 2 h. Glucagon injection also caused a 20% decrease in glucagon binding to the total particulate fraction, which did not occur when binding was measured in the presence of the detergent octylglucoside. The change in glucagon-binding activity in PM and GE fractions resulted mainly from a change in receptor number; affinity remained unaffected (apparent Kd, 0.5 and 5 nM, respectively). A 5- to 10-fold increase in the glucagon content of GE fractions was observed in glucagon-treated rats. Neither the distribution of PM and Golgi marker enzymes nor that of the asialoglycoprotein receptor was affected by glucagon treatment. Regardless of glucagon treatment, glucagon receptors in GE fractions were less sensitive to GTP than receptors in PM fractions with respect to both inhibition of steady state binding and dissociation of prebound ligand. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, glucagon-receptor complexes formed in PM and GE fractions and subsequently cross-linked showed the same apparent mol wt (57 kilodaltons). In addition, they were identically sensitive to N-glycanase treatment, with two major species of lower mol wt generated. However, only cross-linked complexes associated with PM fractions showed detectable GTP sensitivity. GE fractions displayed a GTP-sensitive adenylate cyclase activity that was about 12 times lower than that of PM fractions. In both fractions, activity was stimulated by the addition of forskolin (8-fold) and, to a lesser extent, glucagon (3-fold). In vivo glucagon treatment led to an increase in activity in GE, but not PM, fractions. These results are consistent with the view that upon acute occupancy, hepatic glucagon receptors are rapidly and specifically internalized along with their ligand. During this process, receptor retained structural integrity and uncouple, albeit partially, from other components of the adenylate cyclase system.
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PMID:Ligand-mediated internalization of glucagon receptors in intact rat liver. 131 25

Affinity labeling using [125I-Tyr36]PYY and homobifunctional affinity crosslinking reagents of the rabbit Y2 receptor for peptide YY(PYY) results in specifically labeled proteins of both M(r) = 50,000 to 60,000 and M(r) = 96,000 to 115,000 [1,2]. In this work the glycoprotein nature of affinity labeled Y2 receptor proteins were investigated by enzymatic deglycosylation using neuraminidase, endoglycosidase F (endo F), N-glycosidase F (PNGase F), and O-glycanase treatment. Only N-glycosidase F and neuraminidase increased the electrophoretic mobility of the radiolabeled receptor bands, whereas all other glycosidases did not. PNGase F treatment of both radiolabeled receptor bands electroeluted from gel slices reduced the apparent molecular mass of by 16-17 kDa units, that is M(r) = 96,000 to 79,000 and M(r) = 60,000 to 44,000, indicating removal of N-linked oligosaccharide chains of similar size from both species. Neuraminidase treatment caused slight increases in the electrophoretic mobilities suggesting the presence of terminal sialic residues. It is concluded that the Y2 binding proteins are N-linked complex (sialo)glycoproteins with a minimal core protein size of M(r) = 44,000. Furthermore, based on this sensitivity pattern of the glycosidases, the Asn-linked carbohydrate may be of the tri- or tetra-antennary complex type containing terminal sialic acid residues.
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PMID:Y2 receptor proteins for peptide YY and neuropeptide Y. Characterization as N-linked complex glycoproteins. 132 32

We have purified and characterized a novel 30-kDa glycoprotein (gp30) with TGF alpha-like properties secreted from the estrogen receptor negative breast cancer cell line MDA-MB-231. This factor was immunoprecipitated by an anti-TGF alpha polyclonal antibody and also had TGF alpha-like biological activity, as assayed by EGF radioreceptor assay and anchorage-independent assays. In addition, the novel growth factor stimulated phosphorylation of the EGF receptor and erbB-2 receptor. However, the novel growth factor, unlike EGF and TGF alpha, bound to heparin-Sepharose. Purification of gp30 was obtained to apparent homogeneity by heparin affinity chromatography and subsequent reversed-phase chromatography. Tunicamycin treatment in vivo or N-glycanase deglycosylation in vitro revealed a putative precursor of approximately 22 kDa molecular mass in contrast to the "normal" 16-kDa precursor species for TGF alpha. In vitro translation of total mRNA from MDA-MB-231 cells confirmed the size of the putative precursor. Biochemical characterization of gp30 was begun by V8 protease digestion of the deglycosylated polypeptide and the translated products. Peptide mapping of V8-digested, immunoprecipitated material suggests that the amino acid sequence of this unique protein is distinct from mature TGF alpha and not the result of a posttranslational modification of the precursor. We conclude that this TGF alpha-like (gp30) polypeptide is a novel growth factor with agonistic activity for both EGF and erbB-2 receptors.
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PMID:Purification and characterization of a novel growth factor from human breast cancer cells. 132 10


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