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)

The reducing oligosaccharides released from alpha 1-acid glycoprotein (AGP) by conventional hydrazinolysis have been analyzed by two different mapping techniques, using high-pH anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) and capillary electrophoresis (CE) with uv detection at 190 nm. The CE measurements proved about 4000 times more sensitive than the measurements by HPAE-PAD. The N-glycan pool was fractionated by Mono Q anion-exchange chromatography, and individual fractions so obtained were desialylated using Vibrio cholerae neuraminidase. The resulting asialo-N-glycans were further analyzed by HPAE-PAD, revealing 2 major, 4 intermediate, and 4 small peaks and at least 3 spikes, which counted for at least 13 different asialo-N-glycans. The carbohydrate structures were tentatively assigned by comparison of the Mono Q-separated N-glycans with the known AGP carbohydrate structures and known structures contained in a mapping database that allows structural assignment of N-glycans by mere comparison of retention times. In addition to the hitherto known AGP carbohydrate structures, we have tentatively identified a number of sulfated N-glycans that are currently being analyzed in more detail. We have also compared the glycan pools recovered from AGP using hydrazinolysis and glycopeptidase F (PNGase F). Approximately 40 distinct peaks could be detected in the hydrazinolysis-derived N-glycan pool by either technique (HPAE-PAD and CE), while about 30 distinct peaks were detected in the N-glycan pool derived by PNGase F digestion of the tryptic AGP digest of the same batch of AGP. These differences were attributed to an increased desialylation (approximately 3 mol%) during hydrazinolysis, based on the detection by HPAE-PAD and CE of free sialic acid and monosialylated oligosaccharides in the glycan pool derived by conventional hydrazinolysis. The integrity of the N-glycans' chitobiose core was examined by 500-MHz 1H NMR spectoscopy. The hydrazinolysis procedure could be optimized such that the hydrazinolysis-derived N-glycan pool was chromatographically essentially identical to the PNGase F-derived N-glycan pool. Hydrazinolysis proved best, with practically no loss of N-acetlylneuraminic acid and the closest resemblance to the PNGase F-derived N-glycan pool, using an automated apparatus. Notably, it was recognized that, in our hands, PNGase F digestion in the presence of sodium dodecyl sulfate resulted in partial desialylation of the liberated N-glycans.
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PMID:The mapping by high-pH anion-exchange chromatography with pulsed amperometric detection and capillary electrophoresis of the carbohydrate moieties of human plasma alpha 1-acid glycoprotein. 144 15

The influence of the carbohydrate groups of rhodopsin on its ability to regenerate upon incubation with 11-cis retinaldehyde after photobleaching was examined. Rhodopsin was deglycosylated enzymatically with peptide-N-glycosidase F (PNGase F). Verification of deglycosylation was established by: (a) SDS-PAGE; (b) carbohydrate compositional analysis using high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD); (c) isolation and carbohydrate analysis by HPAEC-PAD and fast atom bombardment-mass spectrometry of the oligosaccharides liberated from rhodopsin; and (d) absence of reactivity with lectins. Deglycosylated rhodopsin, when present either in rod outer segments or after purification, exhibited the same absorption spectrum as the native molecule. After photobleaching, deglycosylated rhodopsin reacted with 11-cis retinaldehyde in a manner similar to the native material, restoring the spectral properties lost after light-exposure. The carbohydrate portion, therefore, was not required for expressing the spectral properties of rhodopsin nor for regeneration of the photobleached visual pigment.
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PMID:Effect of enzymatic deglycosylation on the regenerability of bovine rhodopsin. 152 82

Monosaccharide analysis by high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC/PAD) was used to identify the glycopeptides in the reversed-phase (RP-HPLC) separation of a bovine fetuin tryptic digest (1.6 nmol). This method, requiring no sample derivatization, identified four asparagine-linked (N-linked) glycopeptides and at least seven serine/threonine-linked (O-linked) glycopeptides. Glycopeptide identification was confirmed by Edman sequencing. Monosaccharide quantification of each glycopeptide suggested that all of the N-linked glycopeptides were the complex type and all the O-linked glycopeptides were sialylated. We determined that glycopeptides could be prepared by acidic reversed-phase chromatography with less than 3% loss of N-acetylneuraminic acid (Neu5Ac). The N-linked glycopeptides of bovine fetuin were prepared, digested with N-glycosidase F (PNGase F), and their oligosaccharides analyzed by HPAEC/PAD. These oligosaccharide profiles revealed that the Asn-138 oligosaccharide attachment site contained the majority of the disialylated and monosialylated oligosaccharides. The Asn-158 oligosaccharide attachment site contained the majority of the tetrasialylated oligosaccharides.
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PMID:Identification, quantification, and characterization of glycopeptides in reversed-phase HPLC separations of glycoprotein proteolytic digests. 769 Jan 96

Characterization of monoclonal antibodies (MAbs) produced for therapeutic or diagnostic purposes increasingly includes an assessment of their carbohydrate content. Using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC/PAD), we have analyzed the PNGase F released oligosaccharides of several IgG preparations including human polyclonal IgG, a humanized monoclonal IgG (MAb M115), and a murine monoclonal IgG (MAb MY9-6) derived respectively from serum, hybridoma cultures, and ascites fluid. The N-linked oligosaccharides released by PNGase F treatment of the above IgGs were found to consist mainly of neutral, fucosylated, biantennary species. Comparison of glycosylation of human polyclonal IgG, MAb M115, and MAb MY9-6 revealed differences in the levels of galactosylation and in the levels as well as the form of sialic acid present. HPAEC/PAD oligosaccharide profiling, combined with the use of enzymes (PNGase F, endoglycosidase F2, endoglycosidase H, neuraminidase, beta-galactosidase, and beta-N-acetylhexosaminidase), and monosaccharide analysis allowed making of tentative structural assignments. By performing monosaccharide analysis directly on PVDF electroblotted heavy and light chain bands separated by SDS-PAGE, it was verified that IgGs used in this study were glycosylated predominantly in their heavy chain.
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PMID:Analysis of carbohydrates on IgG preparations. 789 Dec 93

This study characterized the N-glycans of a humanized immunoglobulin G4 (IgG4) expressed in NS/O mouse myeloma cells and directed against the CD18 family of adhesion-promoting receptors on leukocytes. The N-glycans were released from the purified recombinant IgG by N-glycanase treatment, purified by Sephadex G50 chromatography, and fractionated by Bio-Gel P-4 chromatography into three oligosaccharide pools. Each pool was analyzed individually by glycosyl composition analysis, high-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), 600-MHz 1H-NMR spectroscopy, and electrospray-ionization mass spectrometry. In addition, each of the three pools was subfractionated by HPAEC and the isolated subfractions that contained sufficient material were hydrolyzed and analyzed for glycosyl composition by HPAEC-PAD. The overall results indicate the presence of five oligomannoside-type structures (containing 5 to 8 Man residues) which are not usually found in IgG, and the presence of eight diantennary (mostly truncated) N-acetyllactosamine-type structures which are typical of mouse and human IgGs. The N-acetyllactosamine-type structures were heterogeneous with regard to alpha(1-->6) fucosylation of the linkage GlcNAc, and the presence or absence of GlcNAc and/or Gal beta(1-->4)GlcNAc extending the core pentasaccharide (Man3GlcNAc2). No evidence was found for the presence of sialic acid or bisecting GlcNAc residues on the N-acetyllactosamine-type chains. The latter finding suggests that the N-glycans of this humanized IgG are of the mouse type.
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PMID:Structural characterization of the N-glycans of a humanized anti-CD18 murine immunoglobulin G. 790 4

Two-dimensional (2-D) electrophoresis is the preferred method for separating the glycoforms of proteins. The isoforms usually present as 'trains' of spots in the first dimension and may also differ in molecular weight. The primary goal for analyzing the carbohydrate content of glycoprotein spots is to understand the 'rules' which govern the migration of glycoproteins in 2-D electrophoresis. These rules can then be used to produce predictive vectors to interpret changes in glycosylation patterns. Techniques for the analysis of oligosaccharides released from glycoproteins which have been electroblotted to PVDF membrane after one-dimensional (1-D) and 2-D preparative gel electrophoresis are described. The oligosaccharides are removed enzymatically (PNGase F of N-linked oligosaccharides) or chemically (beta-elimination of O-linked oligosaccharides) and separated by high performance anion exchange chromatography (HPAEC-PAD) and identified by electrospray ionization mass spectrometry (ESI-MS) or analyzed directly by ESI-MS. After enzymic removal of the N-linked oligosaccharides the protein spots can be further analyzed by Edman sequence tagging for identification and quantitation of the protein and by acid hydrolysis for monosaccharide analysis of the O-linked oligosaccharides. These approaches have been proved on 1-D PAGE electroblotted bovine fetuin and human glycophorin A and then used to analyze two abundant proteins which separate as glycoforms on 2-D PAGE preparative narrow range (pH 4.5-5.5) blots of human plasma: alpha2-HS glycoprotein (human fetuin) and alpha1-antitrypsin (alpha1-protease inhibitor). It is apparent that both the macroheterogeneity (site occupation) and microheterogeneity (diversity of structures) of the glycosylation contribute to the separation of protein isoforms in 2-D PAGE.
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PMID:Analyzing glycoproteins separated by two-dimensional gel electrophoresis. 963 44

The murine B-lymphocyte hybridoma, CC9C10, was grown at steady state in serum-free continuous culture at dissolved oxygen (DO) concentrations of 10, 50, and 100% of air saturation. The secreted mAb, an IgG1, was purified and subjected to both enzymatic deglycosylation using PNGase F and chemical deglycosylation by hydrazinolysis. Both methods resulted in complete removal of N-linked oligosaccharide chains. Isolated N-glycan pools were analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE) and high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The FACE profiles and corresponding HPAEC-PAD chromatograms of N-linked oligosaccharides obtained by PNGase F digestion and hydrazinolysis provided complementary and corroborating information. The predominant N-linked structures were core-fucosylated asialo biantennary chains with varying galactosylation. There were also minor amounts of monosialylated, and trace amounts of afucosyl, oligosaccharides. A definite shift towards decreased galactosylation of glycan chains was observed as DO concentration in continuous culture was reduced. The vast majority of N-linked glycosylation occurred on the heavy chain. There was no evidence for N-linked glycosylation of the light chain or for O-linked glycosylation of the mAb.
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PMID:Dissolved oxygen concentration in serum-free continuous culture affects N-linked glycosylation of a monoclonal antibody. 968 42

Several different chromatographic methods and a lectin-based assay have been compared for the quantitation of oligosaccharides released from immunoglobulin G (IgG). The analysis of a series of IgG samples purified from the serum of rheumatoid arthritis patients was carried out by these methods to evaluate the percentage of the glycoforms having 0, 1 or 2 galactose residues (G0, G1 and G2) in order to (a) identify the method that can be most widely used for quantitation, (b) accurately define the range of G0 values found in patients with rheumatoid arthritis, and (c) make available a series of characterised standards for distribution to clinical chemistry laboratories. The chromatographic methods involved: release of oligosaccharides by glycoamidase A after protease digestion followed by HPLC analysis of aminopyridine derivatives on reverse phase and normal phase columns; hydrazinolysis treatment with exoglycosidases (G0 mix) and Biogel P4 chromatography of 2-aminobenzamide (2-AB) derivatives; hydrazinolysis and weak anion exchange or normal phase HPLC of 2-AB derivatives; release of oligosaccharides by PNGase F and either Biogel P4 chromatography of 2-AB derivatives or HPAEC-PAD analysis of native oligosaccharides. The G0 values given by these methods compared favourably with each other and a dot blot assay of denatured IgG interaction with Ricinus communis agglutinin and Bandeiraea simplicifolialectin II. The HPLC and HPAEC methods give additional information that may be important in less routine assays.
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PMID:Quantitation of the oligosaccharides of human serum IgG from patients with rheumatoid arthritis: a critical evaluation of different methods. 969 45

Many studies have reported changes in the carbohydrate structure of serum glycoproteins in disease, but this information is often of limited value for understanding disease mechanisms because it is obtained with simple and/or indirect methodologies that determine only one structural feature. On the other hand, more detailed carbohydrate methodologies are time-consuming and require a lot of purified material. Using haptoglobin (Hp) as a model protein, a new procedure was devised that determined the oligosaccharide composition of very small amounts of Hp in a relatively short time. The Hp was purified by batch affinity-chromatography, oligosaccharides were removed with PNGase F, and the oligosaccharide composition of charged species was determined using HPAEC/PAD (Dionex carbohydrate analyser). The method was applied to the analysis of Hp from eight healthy individuals and 37 patients with different inflammatory diseases or cancers. Twenty-seven oligosaccharides were consistently detected, but the majority could not be identified. However, by calculating retention times relative to the sialylated biantennary peak (Neu5Ac(alpha)2-3/6Gal(beta)1-4GlcNAc(beta)1-2Man(alpha)1-6(Neu 5Ac(alpha)2-3/6Gal(beta)1-4GlcNAc(beta)1-2Man(alpha)1-3)Man(beta)1-4G lcNAc(beta)1-4GlcNAc) it was possible to compare profiles quantitatively. Although no peak was identified as disease-specific, characteristic and reproducible profiles were obtained. Particularly striking were reductions in the major peaks in Crohn's disease, rheumatoid arthritis, stomach cancer, accompanied by increases in unidentified peaks. Previous studies suggested that many of the unknown peaks were due to increased sialylation and fucosylation. Only small changes in patterns were observed for breast and ovarian cancer. The new procedure will be very useful in the characterization of oligosaccharide composition of glycoproteins in clinical specimens.
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PMID:Reproducible and sensitive determination of charged oligosaccharides from haptoglobin by PNGase F digestion and HPAEC/PAD analysis: glycan composition varies with disease. 988 48

Isolation of glycosylated 26 kDa rat prolactin and subsequent proper carbohydrate characterization has so far not been reported. In the present work the hormone isoform was isolated to 95% homogeneity by preparative electrophoretic separation on Mini Prep Cell of rat pituitary homogenate. The isoform was then investigated by 2-mercaptoethanol gradient electrophoresis, Cleveland's sequential SDS-PAGE, digestion with endoproteinase Asp-N and N-glycanase. The glycosidic part of the isoform was examined in O-profiling and its monosaccharide composition obtained by FACE and HPAE-PAD analysis. The outcome of the experimental data is: 1) in contrast to unglycosylated 23 kDa rat prolactin, intra-chain S-S bridging is not affected in 26kDa rat prolactin, neither by transiting through a thiol gradient nor in sequential nonreducing/reducing SDS-PAGE; 2) the conformational availability of Asp residues involved in the endoproteinase Asp-N attack is the same in 23- and 26 kDa rat prolactin; the glycan moiety apparently does not cause steric hindrance at this level; 3) no glycosidic N-linkage could be detected, only O-linkage(s); 4) 26 kDa rat prolactin is no glycosyl-phosphaditylinositol-anchored protein; 5) in O-profiling an oligosaccharide chain of Mr +/- 1.4 kDa was recorded; 6) the monosaccharide composition obtained in FACE is peculiar in the sense that next to Fuc, Man, GalNac, GlcNac and NeuAc also Rib was determined; 7) HPAE-PAD analysis identified NeuAc subtypes; 8) in vitro, glycosylation of rat prolactin modulates immune recognition through steric hindrance of the access to the epitope sites.
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PMID:Glycosylated rat prolactin: isolation and structural characterization. 1178 Jul 80


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