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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Flow cytometric analysis employing monoclonal antibodies to the Tn antigen and glycophorin A was used to characterize the erythrocyte populations present in blood samples from individuals with Tn syndrome. Four monoclonal antibodies specific for the Tn antigen, Gal-NAc monosaccharide, on human erythrocytes were obtained from a fusion of splenocytes from a Biozzi mouse immunized with red cells from a Tn individual. These monoclonal antibodies specifically recognize GalNAc monosaccharide sites located on the erythrocyte cell surface sialoglycoproteins, glycophorin A and glycophorin B, and do not bind to fixed normal red cells presenting the Neu-NAc alpha 2-3Gal beta 1-3(NeuNAc alpha 2-6)GalNAc alpha 1-O-Ser(Thr) tetrasaccharide or to fixed neuraminidase-digested cells presenting the Gal-GalNAc disaccharide. The percentages of Tn-positive red cells in samples from six unrelated Tn donors ranged from 28 to 99%. Binding of the glycophorin A-specific monoclonal antibodies showed that the erythrocytes composing the Tn-negative fraction presented normal amounts of the M and N epitopes on glycophorin A. The presumed somatic mutational origin of Tn-positive cells was tested in blood samples from five normal donors; three possible Tn cells were observed after analysis of a total of 1.1 x 10(7) erythrocytes, suggesting that the frequency of such cells in normal individuals is less than 1 x 10(-6).
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PMID:Flow cytometric analysis of erythrocyte populations in Tn syndrome blood using monoclonal antibodies to glycophorin A and the Tn antigen. 169 Jun 28

The present study describes biochemical and morphological differences of pseudophakic bullous keratopathy (PBK) corneas as compared with normal corneas. At the ultrastructural level, all PBK corneas studied had abnormal fibrillar material posterior to the Descemet's membrane. In addition, two of the six PBK buttons had subepithelial fibrocellular materials disrupting the epithelial basement membrane and Bowman's layer. Aggregates of collagen fibrils with 110 nm periodicity were occasionally seen within the stroma of the PBK corneas. Isolation and purification of the collagen from the Descemet's membrane/posterior collagenous layer (DM/PCL) showed an increased amount of material with molecular weight in the range of 50-60K daltons (presumably type VIII collagen) and decreased amounts of higher molecular weight, disulfide-bonded collagenous materials (presumably type IV collagen) as compared with normals. Sugar-specific lectin studies showed an increased deposition of peanut agglutinin (PNA) and Ricinus communis agglutinin I (RCA120) in the DM/PCL of the PBK corneas. Our data suggest that the DM/PCL of PBK corneas have an increased accumulation of terminal B-galactose and B-D-galactose (1-3)-D-N-acetylgalactosamine residues and altered ratios of low and high molecular weight collagenous proteins.
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PMID:Abnormal extracellular matrix in corneas with pseudophakic bullous keratopathy. 232 80

Escherichia coli K12, which possess the K99 plasmid and synthesize K99 fimbriae (E. coli K99), cause severe neonatal diarrhea in piglets, calves, and lambs but not in humans. The organism binds specifically and with high affinity to only two glycolipids in piglet intestinal mucosa as demonstrated by overlaying glycolipid chromatograms with 125I-labeled bacteria. These glycolipids, which are N-glycolyl-GM3 (NeuGc alpha 2-3Gal beta 1-4Glc beta 1-1Cer) and N-glycolylsialoparagloboside (NeuGc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer), occur at about 13 and 0.3 micrograms per gram wet weight of mucosa, respectively. E. coli K99 grown at 18 degrees C, a temperature at which the K99 fimbriae are not expressed, do not bind to these glycolipids. Of the standard glycolipids tested in solid phase binding assays, E. coli K99 binds with highest affinity to N-glycolylsialoparagloboside, with less affinity to N-glycolyl-GM3, and with very low affinity to N-acetylsialoparagloboside. The bacteria do not bind to GM3 (NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1Cer), GM2 (GalNAc beta 1-4[Neu-Ac alpha 2-3]Gal beta 1-4Glc beta 1-1Cer), GM1 (Gal beta 1-3GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4Glc beta 1-1Cer), or several other N-acetylsialic acid-containing gangliosides and neutral glycolipids at the levels tested. N-Glycolylsialyl residues are found in the glycoproteins and glycolipids of piglets, calves, and lambs but not in the glycoproteins and glycolipids of humans. Possibly this distribution of sialyl derivatives explains the host range of infection by the organism.
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PMID:Escherichia coli K99 binds to N-glycolylsialoparagloboside and N-glycolyl-GM3 found in piglet small intestine. 264 97

Carbon-13 NMR spectroscopic studies of native and sequentially deglycosylated ovine submaxillary mucin (OSM) have been performed to examine the effects of glycosylation on the conformation and dynamics of the peptide core of O-linked glycoproteins. OSM is a large nonglobular glycoprotein in which nearly one-third of the amino acid residues are Ser and Thr which are glycosylated by the alpha-Neu-NAc(2-6)alpha-GalNAc- disaccharide. The beta-carbon resonances of glycosylated Ser and Thr residues in intact and asialo mucin display considerable chemical shift heterogeneity which, upon the complete removal of carbohydrate, coalesces to single sharp resonances. This chemical shift heterogeneity is due to peptide sequence variability and is proposed to reflect the presence of sequence-dependent conformations of the peptide core. These different conformations are thought to be determined by steric interactions of the GalNAc residue with adjacent peptide residues. The absence of chemical shift heterogeneity in apo mucin is taken to indicate a loss in the peptide-carbohydrate steric interactions, consistent with a more relaxed random coiled structure. On the basis of the 13C relaxation behavior (T1 and NOE) the dynamics of the alpha-carbons appear to be unique to each amino acid type and glycosylation state, with alpha-carbon mobilities decreasing in the order Gly greater than Ala = Ser greater than Thr much greater than monoglycosylated Ser/Thr approximately greater than disaccharide linked Ser/Thr.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of glycosylation on the conformation and dynamics of O-linked glycoproteins: carbon-13 NMR studies of ovine submaxillary mucin. 277 22

A major mono- and a di-sialoganglioside were isolated and purified to homogeneity from a spontaneous thymoma that occurs in AKR mice. Compositional and methylation analyses and the use of exoglycosidases established the monosialoganglioside to be alpha Neu(2----3)beta Gal(1----3)beta GalNAc(1----4)beta Gal(1----4)Glc(1----4)Cer and the disialoganglioside to be alpha NeuAc(2----8)alpha NeuAc(2----3)beta Gal(1----3)beta GalNAc(1----4)beta Gal(1----4)Glc(1----1)Cer (GD1c). A possible pathway for the biosynthesis of this disialoganglioside is presented.
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PMID:Structure of a new disialoganglioside GD1c from spontaneous murine thymoma. 309 41

A range of monosaccharides was tested for its ability to inhibit the generation of cytotoxic cells during mixed lymphocyte culture. The most discriminatory effect was produced by N-acetyl-D-galactosamine (NADG). The presence of this sugar at the initiation of the coculture significantly inhibited in a dose-dependent manner the induction of a subset of nonspecific activated lymphocyte (ALK) cells preferentially able to lyse the K562 target cell (natural killer, NK-like cells) but had no effect on the generation of either specific cytotoxic T lymphocytes or another separate subset of ALK cells mediating lysis of an NK-insensitive melanoma cell line. The addition of conditioned medium containing interleukin 2 and interferon (IFN) at the start of culture reversed the inhibitory effect of the sugar. Under conditions of limiting dilution, the frequency of NK-like precursors ranged from 1/50 to 1/1200 with different mononuclear cells (MNC) and in all cases the presence of NADG from Day 0 of culture selectively decreased the frequency of these precursors. At the concentrations used NADG had no effect on NK-like cell cytolysis once generated. The addition of recombinant gamma-IFN did not abrogate the inhibitory effect of NADG and in MLC of some individuals decreased the frequencies of ALK cell precursors. These data provide further evidence for the heterogeneity of ALK cells and indicate that what is usually referred to as NK-like cell activity in in vitro culture is mediated by a subpopulation of MNC which are activated and induced to differentiate along a pathway independent of that of other ALK subsets.
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PMID:In vitro generation of human activated lymphocyte killer cells. II. N-acetyl-D-galactosamine inhibits a distinct subpopulation of human activated lymphocyte killer cells generated in mixed lymphocyte culture. 315 1

Purified human colonic mucin contains six distinct components which may be separated by DEAE-cellulose chromatography. Past studies defined the structure of oligosaccharide side chains from the most abundant species III, IV, and V which elute at intermediate salt concentrations. In these studies the structures of oligosaccharide side chains liberated from the remaining early and late eluting species I, II, and VI were determined after isolation by sequential conventional and high performance liquid chromatography through combination of gas chromatography, methylation analysis, and sequential glycosidase digestion. Mucin species I, II, and VI contained a less varied array of discrete oligosaccharide structures than that observed in the major mucin components. Mucin species I and II contained five and 10 structures, respectively, which account for 68 and 71% of total oligosaccharide content in these fractions. The predominant oligosaccharides of mucin species I included three neutral structures: a disaccharide GlcNAc beta (1-3)GalNAc-ol, a trisaccharide Gal beta (1-4)GlcNAc beta (1-3)GalNAc-ol, and a tetrasaccharide GlcNAc beta (1-4)Gal beta (1-4)GlcNAc beta (1-3)GalNAc-ol as well as two acidic components representing the sialylated forms of two of these oligosaccharides. Mucin species II contained these same oligosaccharides as well as four additional acidic structures, notably a disaccharide Neu alpha (2-6)GalNAc-ol and a hexasaccharide Gal beta (1-4)GlcNAc beta (1-3)Gal beta (1-4)GlcNAc beta (1-3) (NeuAc alpha (2-6))-GalNAc-ol, not identified in any other mucin species. The late eluting mucin species VI contained at least five discrete neutral oligosaccharides and six major acidic structures. While the majority of these structures had been previously isolated from the earlier eluting mucin species IV and V, species VI also contained di- and trisialylated oligosaccharides not identified in other mucin species. In conjunction with earlier studies of the major mucin species III, IV, and V, these data define the range of oligosaccharide structures present in human colonic mucin. These studies demonstrate that human colonic mucin possesses species with characteristic and distinguishable combinations of oligosaccharides which reflect variations of common core structures.
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PMID:Oligosaccharide structures of isolated human colonic mucin species. 406 81

Five major sialyloligosaccharides and a sialylglycopeptide have been isolated from normal human urine by charcoal adsorption, gel filtration, ion-exchange chromatography, and paper chromatography. Structural studies including gas-liquid chromatography of monosaccharide and disaccharide derivatives, methylation analysis, glycosidase treatments, and CrO3 oxidation indicated the following structures for the compounds: 1, NeuAc(alpha 2-6)Gal(beta 1-4)Glc; 2, NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc; 3, NeuAc(alpha 2-3)Gal(beta 1-4)Glc; 4, NeuAc(alpha 2-3)Gal(beta 1-4) GlcNAc; 5, NeuAc(alpha 2-3)Gal(beta 1-3) [Neu-Ac(alpha 2-6)]GalNAc; and 6, NeuAc(alpha 2-3)Gal(beta 1-3) [NeuAc(alpha 2-6)]GalNAc (alpha 1-O)Ser. Compounds 4, 5, and 6 have not been described in a free form before. The presence of compound 5 in urine may suggest that it derives from glycoproteins through a catabolic pathway involving cleavage of the carbohydrate-peptide linkage by an endo-N-acetylgalactosaminidase. The predominating sialyloligosaccharides in urine were compounds 3 and 4. The predominance of the compounds with the sialyl(alpha 2-3) linkage is of interest in view of the recent discovery of uropathogenic Escherichia coli strains with binding specificity for sialyl(alpha 2-3)galactosides.
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PMID:Isolation and structural characterization of five major sialyloligosaccharides and a sialylglycopeptide from normal human urine. 662 86

The carbohydrate structure and complete amino acid sequence of a human lambda-type immunoglobulin light chain, protein Sm lambda has been determined. The protein was isolated from the urine of a patient with a plasma cell dyscrasia resembling gamma-heavy-chain disease. 13 tryptic peptides covering the entire polypeptide chain of 135 residues were isolated from the aminoethylated protein, and 15 chymotryptic peptides, accounting for 131 residues, were recovered from the carboxymethylated protein. The sequence of 18 of these peptides was partially or completely determined by the Edman-dansyl technique or C-terminal analysis, permitting the establishment of the complete primary structure of the polypeptide chain. The sequences established that this light chain possessed an intramolecular deletion of 81 amino acid residues. The N-terminal 30 residues showed considerable homology with other lambda chains of subgroup II. The defect began at position 31, in the first hypervariable region, and encompassed the remainder of the variable region through position 109. The constant region was fully intact and normal synthesis recommenced with a glutaminyl residue at position 110, the first residue of the constant region. This light chain contained carbohydrate in the hypervariable region just preceding the deletion. The precise number and locations of the oligosaccharide chains were established by amino acid sequence analysis of glycopeptides isolated from proteolytic hydrolysates by chromatography on Bio-Gel P-6 columns. These studies showed that protein Sm lambda contains one N-glycosidically-linked chain attached to asparagine-25 and one O-glycosidically-linked oligosaccharide chain attached to serine-21. The structures of the oligosaccharide chains were determined by methylation analysis, gas chromatography and hydrolysis with specific glycosidases. The structure of the N-glycosidically-linked chain was NeuAc(alpha 2 leads to 6)Gal(beta 1 leads to 4)GlcNAc(beta 1 leads to 2)Man(alpha 1 leads to 6)[NeuAc(alpha 2 leads to 6)Gal(beta 1 leads to 4)GlcNAc(beta 1 leads to 2)Man(alpha 1 leads to 3)]Man(beta 1 leads to 4)GlcNAc(beta 1 leads to 4)[Fuc alpha 1 leads to 6]GlcNAc leads to Asn. The second O-glycosidically-linked chain was a disialylated tetrasaccharide with the structure, Neu(alpha 2 leads to 3)Gal(beta 1 leads to 3)[NeuAc(alpha 2 leads to 6)GalNAc leads to Ser. This mucin-type disialylated tetrasaccharide in close proximity to N-asparagine-linked chains has not been previously observed in the oligosaccharide chains of immunoglobulins.
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PMID:Localization of the carbohydrate units in a human immunoglobulin light chain, protein Sm lambda. 678 88

The oligosaccharide units of glycophorin isolated from porcine erythrocyte membranes were released by alkaline borohydride treatment and purified by gel filtration and ion-exchange chromatography. Structures of the O-glycosidic oligosaccharides were determined by methylation analysis, the methylated sugar being identified by gas-liquid chromatography-mass spectrometry and nitrous acid deamination after hydrazinolysis. The major oligosaccharide was a trisaccharide, Gal(1 leads to 3)[Neu-NGly(2 leads to 6)]GalNAc. The other oligosaccharides were larger and contained Glc-NAc. One was a pentasaccharide, Gal(1 leads to 3)Gal(1 leads to 4)GlcNAc(1 leads to 3)Gal(1 leads to 3)GalNAc. The structure of the trisaccharide was also analyzed by direct-probe mass spectrometry of the permethylated derivative, and the result obtained was consistent with the proposed structure.
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PMID:Isolation and characterization of alkali-labile oligosaccharide units from porcine erythrocyte glycophorin. 707 49


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