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)

The amino acid sequences of the kainate binding proteins (KBPs) from frog and chicken brain are homologous with the carboxy terminal half of the rat brain AMPA receptors. In this study, we have characterized the oligosaccharide side chains present on the KBPs from chicken and frog brain, and the AMPA receptors (GluR1, GluR2, and GluR3) from rat brain. Deglycosylation of the asparagine-linked carbohydrates present on the chicken, frog, and rat receptor subunits with N-glycanase, resulted in decreases in the relative molecular weights (M(r)) of 3.4, 3.4, and 5.1 kDa respectively. Thus the percent of asparagine linked carbohydrate (based on M(r) values derived from SDS polyacrylamide gels) of the 49 kDa chicken, the 48 kDa frog, and the 107 kDa receptor rat subunits is 6.9, 7.1, and 4.8 percent respectively. No shifts in the M(r) were detected after treatment with neuraminidase indicating that sialic acid does not appear to be a major component of these receptors. Lectin binding studies demonstrated that both asparagine-linked and serine/threonine-linked oligosaccharides were present in the chicken, frog, and rat proteins. The data indicate that at least one of the asparagine linked oligosaccharide side chains appear to be of the complex or non-bisected hybrid type in all three species. The similarities in the glycosyl moieties of the chicken and frog kainate KBPs and the rat brain AMPA receptors suggests that the homology in the amino acid sequences between these proteins may extend to homology in their oligosaccharide sides chains as well.
Brain Res 1992 Sep 11
PMID:Characterization of the oligosaccharide side chains on kainate binding proteins and AMPA receptors. 133 Feb 12

Platelet-derived growth factor (PDGF) is believed to be a critical mediator of vascular smooth muscle cell (SMC) proliferation. Because insulin-like growth factor (IGF) I (IGF-I) functions as a progression factor for the mitogenic effects of PDGF, we hypothesized that IGF-I gene expression and the production of IGF binding proteins (IGFBPs) by cultured rat aortic SMCs might be regulated by one or more of the three isoforms of PDGF: PDGF-AA, -BB, and -AB. IGF-I gene expression was highly dependent on cell density: IGF-I mRNA transcripts decreased markedly as a function of cell confluence. IGF-I mRNA content was inhibited to a similar degree by PDGF-AA, -BB, and -AB through a mechanism requiring protein synthesis. The inhibition was readily apparent at 4 hours, reaching approximately 25% of control levels after 24 hours. Radioimmunoassayable IGF-I was only barely detectable in SMC-conditioned serum-free medium and not significantly modulated by PDGF. Western ligand blot revealed that vascular SMCs release 30-kd and 24-kd IGFBP into serum-free conditioned medium. PDGF isoforms did not significantly alter release of the 30-kd IGFBP but evoked a fivefold to sixfold increase in the 24-kd IGFBP. The 24-kd IGFBP was found to comigrate with IGFBP-4, a recently identified binding protein that inhibits IGF action. The 30-kd protein was not merely a glycosylated form of IGFBP-4, because it was not sensitive to N-glycanase digestion. PDGF-AA, -BB, and -AB markedly induced expression of IGFBP-4 mRNA in a time- and concentration-dependent fashion. Vascular SMCs also express IGFBP-2 mRNA, but its abundance was not induced by PDGF. In conclusion, PDGF evokes a complex pattern of regulation of genes in the IGF/IGFBP system. By inhibiting IGF-I production and specifically inducing biosynthesis of the inhibitory binding protein IGFBP-4, PDGF may set in motion mechanisms to limit the final magnitude of the mitogenic response.
Circ Res 1992 Sep
PMID:Platelet-derived growth factor isoforms decrease insulin-like growth factor I gene expression in rat vascular smooth muscle cells and selectively stimulate the biosynthesis of insulin-like growth factor binding protein 4. 137 93

A comparative study was undertaken to characterize the linkages of L-fucose in N-glycans of plasma membrane glycoproteins from Morris hepatoma 7777, host liver and kidney cortex, as well as from rat serum. After in-vivo radiolabelling of rats with L-[6-3H]fucose, the asparagine-linked carbohydrate chains were released from delipidated plasma membrane glycoproteins, as well as from serum glycoproteins, by enzymic digestion with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase from Flavobacterium meningosepticum. They were then converted to their corresponding oligosaccharide alditols by reduction with sodium borohydride. Two specific alpha-L-fucosidases from almond emulsin and from Aspergillus niger, combined with affinity HPLC on immobilized Aleuria aurantia lectin were used to study the linkage of L-fucose in the oligosaccharide chains. Fucose alpha 1-2 linked to galactose, was present only in the plasma membrane of hepatoma 7777 (18% of total L-[3H]fucose in N-glycans), but was not expressed in host liver, kidney cortex and serum. None of the investigated sources contained an appreciable amount of fucose alpha 1-3/4 linked to N-acetyl-D-glucosamine. All the radioactively labelled oligosaccharides from host liver, kidney cortex and serum, but only 82% of these oligosaccharides from hepatoma, contained alpha-fucosyl residues linked at the C6 position of the proximal N-acetyl-D-glucosamine.
Eur J Biochem 1992 Sep 15
PMID:Occurrence of alpha 1-2-fucosylation in membrane glycoproteins of Morris hepatoma 7777 but not in liver. Aberrant type of fucosylation in a malignant tissue. 139 74

Barley (1----3,1----4)-beta-glucan 4-glucanohydrolase (EC 3.2.1.73) isoenzyme EII carries 4% by weight carbohydrate and is more stable at elevated temperatures than isoenzyme EI, which has no associated carbohydrate. The relationship between carbohydrate content and thermostability has been investigated by treatment of the two isoenzymes with N-glycopeptidase F (EC 3.5.1.52). Removal of carbohydrate from isoenzyme EII results in a decrease in the enzyme's thermostability, but treatment of isoenzyme EI with the N-glycopeptidase F has no effect. In addition, removal of a single N-glycosylation site in isoenzyme EII (Asn190-Ala-Ser) by site-directed mutagenesis of the corresponding cDNA led to a reduction in thermostability, while the introduction of this site into isoenzyme EI enhanced stability. We conclude that N-glycosylation of Asn190 enhances the stability of isoenzyme EII at elevated temperatures, but that other factors related to their primary structures also contribute to the differences in thermostabilities of the barley (1----3,1----4)-beta-glucanases.
FEBS Lett 1992 Sep 14
PMID:Differences in the thermostabilities of barley (1----3,1----4)-beta-glucanases are only partly determined by N-glycosylation. 151 97

The DNA sequence encoding the complete HSV-1 glycoprotein G (gG) was inserted into a baculovirus transfer vector and recombinant viruses expressing gG were isolated. Three gG-related recombinant baculovirus expressed peptides of 37, 42, and 44 kDa were detected by Western blotting using monoclonal antibody to gG. The 42- and 44-kDa species were susceptible to tunicamycin, Endoglycosidase H (Endo-H), and N-glycosidase F (PNGase F) treatments, suggesting that they were glycosylated. Although only very low levels (approximately 1:10) of HSV-1-neutralizing antibody were produced in mice vaccinated with the baculovirus gG, these mice were partially protected from lethal challenge with HSV-1 (75-78% survival) and this level of protection was highly significant (P = 0.002). This is the first report to show that vaccination with HSV-1 gG can provide mice with any level of protection against lethal HSV-1 challenge.
Virology 1992 Sep
PMID:Baculovirus-expressed glycoprotein G of herpes simplex virus type 1 partially protects vaccinated mice against lethal HSV-1 challenge. 152 31

We have isolated four insulin-like growth factor binding proteins (IGFBPs) from adult human serum by insulin-like growth factor (IGF) I affinity chromatography and high performance liquid chromatography. A 36-kDa binding protein (BP), not digestible with N-glycanase, is increased in patients with extrapancreatic tumor hypoglycemia and during IGF I administration in healthy adults. Its 38 NH2-terminal amino acids are identical to those of an IGFBP sequence derived from a human cDNA that cross-hybridizes with the rat IGFBP-2 cDNA. With probes encoding a NH2-terminal, COOH-terminal, and a middle region of this protein we have obtained three cDNA clones from a Hep G2 cDNA library; one encodes human IGFBP-2, and the other two presumably represent unspliced heteronuclear and alternatively spliced mRNA, respectively. A 28-30-kDa IGFBP represents a novel BP species in human serum. Its 30 NH2-terminal amino acids are not homologous to IGFBP-1, -2, or -3. It is not digestible with N-glycanase and does not bind 125I-IGF I. The NH2-terminal sequences of a 42/45- and a 31-kDa IGFBP are identical to that of human IGFBP-3. The 42/45-kDa proteins are two glycosylation variants of BP-3. The 31-kDa protein presumably is a degradation product of BP-3 that lacks the COOH terminus. It is likely that the different IGFBPs modulate auto-/paracrine and endocrine effects of IGFs on growth and metabolism in a different and specific manner.
J Biol Chem 1990 Sep 05
PMID:Isolation from adult human serum of four insulin-like growth factor (IGF) binding proteins and molecular cloning of one of them that is increased by IGF I administration and in extrapancreatic tumor hypoglycemia. 169 83

It has been well documented that rat AFP is separated into two discrete fractions electrophoretically and by ion exchange chromatography and it is generally accepted that the two forms of AFP, "Slow" and "Fast" variants, have different charges and molecular sizes. In this paper, the molecular basis of electrophoretic variants of rat alpha-fetoprotein (AFP) was studied. Carbohydrate-free rat AFP was electrophoretically homogeneous. Stepwise conversion of molecular sizes by deglycosylation with glycopeptidase F and the specific activities of the variants of which sugar chains were radiolabelled suggest that "Slow" and "Fast" variants have two and one sugar chains per molecule, respectively.
Hokkaido Igaku Zasshi 1991 Sep
PMID:[Electrophoretic variants of rat alpha-fetoprotein]. 172 Apr 12

An 80 KDa glycoprotein (gp 80), known to be released predominantly from the apical surface by filter-grown Madin-Darby canine kidney cells, was purified to electrophoretic homogeneity. Purified gp 80 was found to have a disulfide-bonded dimeric structure, and appeared to exist in two molecular forms, a major (high-molecular weight) form consisting of a 46 KDa subunit and a 39 KDa subunit and a minor (low-molecular weight) form consisting of a 46 KDa subunit and a 33 KDa subunit. Upon de-glycosylation by N-glycanase treatment, the 46 KDa subunit was converted to a 25.6 KDa form, whereas both the 39 KDa and the 33 KDa subunit gave rise to a 21.1 KDa form. V8 protease mapping of deglycosylated polypeptides revealed the 39 KDa and the 33 KDa subunit to have nearly identical band patterns, which also exhibited a high degree of homology to that derived from the 46 KDa subunit. Radioimmunoassays revealed that the binding of the purified gp 80 to fibrinogen (or heparin) was dependent on both pH and divalent cations. Furthermore, binding of gp 80 to immobilized fibrinogen (or heparin) was inhibited in the presence of free fibrinogen (or heparin) added in the assay mixture.
Biochem Int 1991 Sep
PMID:Purification and characterization of the apically secreted 80 KDa glycoprotein from Madin-Darby canine kidney (MDCK) cells. 177 37

The major B cell Ag receptors, membrane (m) IgM and mIgD, are noncovalently associated with disulfide-linked heterodimers of alpha, beta, and gamma glycoproteins. The beta and gamma chains have apparent molecular masses of 37 and 34 kDa, respectively, and are associated with both mIgM and mIgD. Receptor alpha chains, however, exhibit Ig isotype specificity. IgM-alpha and IgD-alpha have apparent molecular masses of 32 and 33 kDa, respectively. Recently, the alpha chain of the IgM Ag receptor complex was identified as the product of the mb-1 gene, and the beta and gamma chains were characterized as products of the B29 gene. The failure of mb-1 cDNA to hybridize with mRNA from J558 delta m2.6 plasmacytomas expressing surface mIgD in association with IgD-alpha has led to the conclusion that IgM-alpha and IgD-alpha are not closely related. In this report we have used protein biochemical methods to characterize differences in the mIgM- and mIgD-associated alpha chains. In addition to a slightly greater apparent m.w., IgD-alpha was slightly more acidic than IgM-alpha. The alpha chains had nearly identical proteolytic peptide maps, and were also noted to have multiple loci of identity with MB-1 based on amino terminal sequencing and immunoblotting. In an attempt to determine whether the alpha chains differed as a result of differential posttranslational modification, they were compared after deglycosylation with N-glycanase. The results indicate that the apparent m.w. as well as isoelectric point differences are primarily due to differential N-linked glycosylation. These studies indicate that IgM-alpha and IgD-alpha are products of the mb-1 gene or closely related genes.
J Immunol 1991 Sep 01
PMID:Alpha-chains of IgM and IgD antigen receptor complexes are differentially N-glycosylated MB-1-related molecules. 188 Apr 17

Biochemical properties of the concanavalin A-binding 43-kDa glycoprotein (gp43) of Paracoccidioides brasiliensis and its deglycosylated form were compared. Deglycosylation was achieved by treatment with trifluoromethanesulfonic acid, endoglycosidase H, N-glycanase, or metabolically, by growing cells with tunicamycin. The resulting antigen in all cases had Mr 38,000, and probably derived from the gp43 by loss of N-linked high-mannose oligosaccharide chains. The presence of galactopyranose units in the carbohydrate chains was suggested by antigen binding to peanut lectin. Pulse and chase experiments using [35S]methionine metabolic labeling of P. brasiliensis growing in the presence of tunicamycin showed that the N-linked chains of gp43 are not required for antigen secretion. The 38-kDa antigen was more susceptible than the native antigen to the action of papain and pronase, thus indicating a protective role of the carbohydrate moiety against proteolysis. Both forms are equally resistant to endogenous proteases at neutral pH. The gp43, itself, has a proteolytic activity at pH 5-6, but not at neutral pH. Deglycosylation with endoglycosidase H or tunicamycin preserved epitopes in the 38-kDa molecule reactive with (a) antibodies from patients with paracoccidioidomycosis, or rabbit immunized with the gp43 and (b) mouse monoclonal antibodies against the gp43 antigen. The present results provide a basis for the understanding of diagnostic reactions and fungal virulence involving the gp43 exocellular antigen of P. brasiliensis.
Arch Biochem Biophys 1991 Sep
PMID:The 43-kDa glycoprotein from the human pathogen Paracoccidioides brasiliensis and its deglycosylated form: excretion and susceptibility to proteolysis. 189 73


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