UMLS:C0027960 - FACTA Search

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Query: UMLS:C0027960 (mole)
21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fractions of complex glycosphingolipids were prepared from adult, cord, and i phenotype erythrocytes by the method elaborated for the isolation of poly(glycosyl)ceramides. In contrast to poly(glycosyl)ceramides which comprise on the average 30 glycosyl units and about 5 branching points, i.e. 3,6-di-O-substituted galactopyranosyl residues, per mole of glucose, complex glycosphingolipids from cord and i erythrocytes comprise 6 and 15 glycosyl units respectively and only 0.7 branching points. The latter substances exhibited also a high i activity which was not detected in poly(glycosyl)ceramides. Erythrocyte membranes were labeled with radioactive N-acetylgalactosamine (GalNAc) from UDP-GalNAc using a purified A-blood-group gene-specified transfered of GalNAc. It was found that electrophoretic mobilities in dodecylsulfate-gel electrophoresis of all glycoconjugates which accepted GalNAc were increased in i as compared to I membranes. We conclude that the absence of highly branched glycosphingolipids in cord and i erythrocytes as well as the reduction of apparent molecular weights of the glycoconjugates, which are substrates for A-gene-specified transferase of GalNAc, result from a single cause, that is an inadequacy of the biosynthetic process which is responsible for the formation of GlcNAc1 leads to 6Gal structures.
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PMID:Immunochemistry of Ii-active glycosphingolipids of erythrocytes. 45 78

Very complex glycosphingolipids with A, H and I blood-group activities were isolated from human erythrocyte membranes. The membranes were obtained from erythrocytes of blood group A, A2 and O respectively. A general formula for the antigens is: (Fuc)3-4(Gal)n(LlcNAc)n-2(Glc)1(Sphingosine)1(where Fus is fucose, Gal is galactose, GlcNAc is N-acetylglucosamine and Glc is glucose) with values of n ranging from 10-27. A-active preparations contain additionally 2-3 residues of N-acetylgalactosamine. In view of the unusual complexity of these compounds they were designated poly(glycosyl)ceramides (formerly megaloglycolipids). Individual poly(glycosyl)ceramide fractions were isolated from A erythrocytes and were found to differ by about 8 glycosyl residues per molecule forming a series of compounds with 22, 30, 38, 51 and 59 glycosyl residues per mole. Structural studies indicate that the main sequence of poly(glycosyl)ceramides consists of the residues of galactopyranose and 2-deoxy-2-acetamidoglucopyranose substituted at 3 and 4 position respectively. These residues are probably alternating. N-Acdtylglucosamine substituted at 3 position was not found in poly(glycosyl)ceramides. Brances of poly(glycosyl)ceramides originate from 3 and 6 position of galactopyranosyl residues. The number of branches is proportional to the degree of molecular complexity. In poly(glycosyl)ceramides isolated from A and A2 erythrocytes the branches are terminated with the following structures GalNAc alpha 1 leads to 3 [Fuc alpha 1 leads to 2] Gal; Fuc alpha 1 leads to 2 Gal and Gal (presumably Gal beta 1 leads to 4 GlcNAc). In poly(glycosyl)ceramides from A cells the total number of A and H-active structures per average molecule of 30-35 glycosyl residues amounts to 2.1 and 1.2 respectively while the number of terminal galactose structures is 1.8. For poly(glycosyl)ceramides from A2 erythrocytes the corresponding figures are 0.75, 3.5, and 2.1 respectively. Poly(glycosyl)ceramides from O cells comprise about 3.8 H-active structures and 1.8 terminal galactopyranosyl residues. In poly(glycosyl)ceramides with high "n" values the number of terminal galactose structures is increased. These fractions display high blood-group I activity. However, the removal of terminal galactose with beta-galactosidase affects I-activity only slightly.
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PMID:Isolation and characterization of poly(glycosyl)ceramides (megaloglycolipids) with A, H and I blood-group activities. 82 47

Human bronchial mucin from a patient suffering from chronic bronchitis was solubilized in aqueous solution containing sodium azide and protease inhibitors and purified by Sepharose 4B and 2B column chromatography. The mucin was further purified by cesium bromide density gradient centrifugation. Sodium dodecyl sulfate-polyacrylamide gel (7.5%) electrophoresis of this material showed high-molecular-weight mucin component(s) at the top of the gel. Chemical analysis of this preparation indicated a typical mucin profile of amino acids and carbohydrates. Ion-exchange chromatography resulted in resolution of the purified mucin into neutral and acidic fractions. Comparison of the chemical composition of these two fractions showed higher mole percentage of threonine, serine, sialic acid, and sulfate in the acidic fraction. Chemical deglycosylation of the purified mucin preparation with trifluoromethane sulfonic acid was carried out at 20 degrees C for 3 1/2 h. Sialic acid, fucose, galactose, and N-acetylglucosamine were completely removed, whereas traces of N-acetylgalactosamine were still detected. High-pressure liquid chromatography of the deglycosylated products from native, neutral, and acidic mucin preparations resulted in a principal peptide, P1, with identical amino acid composition. Cyanogen bromide (CNBr) treatment of the peptide P1 from neutral and acidic mucins and subsequent fractionation of the fragments by high-pressure liquid chromatography resulted in similar peptide profiles. The P1 peptide fraction was further subjected to high-pressure liquid chromatography in a second solvent system, which resulted in two peaks, P1a and P1b. Gel filtration of both peptides in 6 M guanidine hydrochloride indicated a single peak with molecular weight of approximately 97 kDa. The amino acid profile of the two peptides was dominated by high levels of threonine, serine, and proline, which combined accounted for nearly 39% of the total residues, and in most respects, the profile resembled that of native mucin. End-group analysis of the peptide P1a indicated a blocked N-terminus, whereas serine was found to be the N-terminal amino acid in the peptide P1b. Rabbit antibodies prepared against the peptide P1 from native tracheal mucin reacted strongly with neutral and acidic mucin as well as the mucin from human colon. Both neutral and acidic human tracheal mucins were immunologically reactive with mouse monoclonal antibody HMPFG-2, which was prepared against human mammary mucin. However, the response of this antibody to human colonic mucin was rather weak.
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PMID:Neutral and acidic human tracheobronchial mucin. Isolation and characterization of core protein. 237 52

A heterobifunctional linking reagent containing a masked aldehydo group and acyl hydrazide was synthesized for coupling of glycopeptides and other amino-containing compounds to proteins. After conversion to acyl azide, the reagent reacts with the amino group of a glycopeptide, and the modified glycopeptide is deacetalized with a weak acid to unmask the aldehydo group, which is then conjugated to bovine serum albumin (BSA) by reductive alkylation with pyridine-borane. The overall reaction scheme proceeds under relatively mild conditions. When the protein amino group was in a large excess (greater than 6-fold) of the aldehyde reagent, the efficiency of conjugation was as high as 88% even at submicromole levels. As a test case for application of this reagent, 6-aminohexyl beta-D-galactopyranoside (Gal-AH) was attached to the linking reagent and conjugated to BSA at various aldehyde-to-protein molar ratios ranging from 25 to 200. The level of O-galactosyl residue incorporated into BSA by this reagent far exceeded that observed in a similar reductive alkylation involving S-galactoside reagents [Lee, R. T., & Lee, Y. C. (1980) Biochemistry 19, 156-163]. By use of the present conjugating procedure, as many as 112 mol of Gal-AH residues were incorporated per mole of BSA, which represents near total modification of the amino groups. Some binding characteristics of the new BSA derivatives were studied in the mammalian hepatic galactose/N-acetylgalactosamine specific lectin system along with other types of BSA derivatives (containing S-galactosyl residues). In general, the behavior of the new derivatives was similar to that of other types. For instance, the affinity increased exponentially at low sugar substitution levels (up to 30 mol of galactosyl residues/mol of BSA), and the slope of exponential increase and affinity at a given sugar substitution level was similar to those of other types.
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PMID:Efficient coupling of glycopeptides to proteins with a heterobifunctional reagent. 247 Apr 4

Myelin basic protein (MBP), isolated from normal human myelin, was glycosylated with UDP-N-acetyl-D-galactosamine and a glycosyltransferase isolated from porcine submaxillary glands. MBP containing 0.85 mol of N-acetyl-D-galactosamine per mole of protein was oxidized at carbon 6 by galactose oxidase and complexed with a spin-label, Tempoamine, in order to study its interactions with lipids. When the spin-labeled MBP was reacted with lipid vesicles consisting of DSPG, DPPG, and DMPG, most of the spin-label was motionally restricted in the gel phase, with a correlation time greater than 10(-8)s. The motion increased with increasing temperature and was sensitive to the lipid phase transition. Interaction with the gel phase of DPPA caused much less motional restriction of the probe. However, melting of the lipid allowed increased interaction and motional restriction of the probe, which was only partially reversed on cooling back to the gel phase. The motional restriction of the probe in these lipids is attributed to its penetration partway into the lipid bilayer in both the gel and liquid-crystalline phases. The fact that the probe bound to the protein can penetrate partway into the bilayer suggests that other hydrophobic side chains and residues of the protein can similarly penetrate into the bilayer. Additional evidence for penetration was provided by digestion of the lipid-bound protein with endoproteinase Lys-C. When nonglycosylated and glycosylated MBP in solution was treated with Lys-C, extensive digestion occurred. A single radioactive peptide which eluted at 25 min was identified as residues 92-105.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction of glycosylated human myelin basic protein with lipid bilayers. 247 62

Apolipoprotein C-III (apo C-III) is a 79 amino acid glycoprotein. The sugar moiety of apoC-III is attached to amino acid residue 74 and is thought to consist of 1 mole of galactose, 1 mole of N-acetyl-galactosamine, and either 0, 1, or 2 moles of sialic acid. This results in three isoproteins called C-III0, C-III1, and C-III2 designated by the number of sialic acid residues. It has been assumed, although not experimentally tested, that apoC-III0 lacks sialic acid residues but possesses the D-galactosyl-(1-3)-N-acetyl-D-galactosamine sugar backbone. To verify the structure of the three apoC-III isoproteins, we applied the method of 252Cf plasma desorption mass spectrometry to measure the exact molecular weight (Mr) of each of the isoproteins. Our data confirmed the proposed structure of apoC-III1 and apoC-III2. However, the difference in mass between apoC-III1 (9420.6, 9420.0, 9422.2 daltons) and apoC-III0 (8763.9, 8764.9, 8765.5 daltons, respectively, in three subjects) suggests that the latter is missing not just sialic acid but the entire sugar moiety. This finding may have important implications for the metabolism of apoC-III. The accuracy and reproducibility of Mr measurements described in this paper suggest that this technique holds promise for the detection of apolipoprotein amino acid substitutions or modifications undetected by conventional techniques such as isoelectric focusing.
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PMID:Apolipoprotein C-III0 lacks carbohydrate residues: use of mass spectrometry to study apolipoprotein structure. 261 77

Eggs of Urechis caupo are surrounded by a congruent to 0.9 micrometer thick egg envelope and, attached to that, a peripheral jelly layer about 3 micrometers thick. Before fertilization, the sperm undergoes the acrosome reaction and binds to the egg envelope. As part of a study of the induction of the acrosome reaction and sperm binding in Urechis, we have developed a method to prepare an egg envelope fraction by differential centrifugation. The isolation procedure removes much of the jelly layer, but does not alter the fine structure of the envelope. When a sperm contacts an isolated envelope, it undergoes a normal acrosome reaction and binds to the envelope's outer face. Electrophoresis of the envelope fraction on sodium dodecyl sulphate (SDS)/polyacrylamide gels revealed six major components stained by Coomassie Blue, of which four are stained by the periodic acid-Schiff reagents (PAS). To measure the degree of enrichment of the envelope fraction, envelopes were isolated from eggs that had been externally radio-iodinated; the specific activity of the envelope fraction was 17 +/- 3 times greater than that of intact eggs. The amino acid composition of the envelope fraction is dominated by Gly (19 mole %), Asx (11%), Thr (11%), Ser (8%), Ala (8%) and Glx (8%). The sugars fucose, xylose, mannose, galactose, glucose, N-acetylglucosamine and N-acetylgalactosamine were detected by gas-liquid chromatography. We also investigated whether the egg envelope changes at fertilization. No change was detected in the electrophoretic 125I pattern of externally radio-iodinated eggs, and the envelope fractions prepared from unfertilized and fertilized eggs produced the same Coomassie Blue pattern on SDS/polyacrylamide gels.
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PMID:Isolation and partial characterization of Urechis caupo egg envelopes. 404 Sep 20

Glycosaminoglycan isolated from urine of a patient with the Hurler-Scheie compound syndrome consisted of dermatan sulfate (60%), heparan sulfate (34%) and chondroitin sulfate (6%). About 60% of both dermatan and chondroitin sulfates had molecular weight 8,000-10,000, while 95% of the heparan sulfate had molecular weight less than 6,000. The total sulfate content of the glycosaminoglycans increased with decrease in molecular weight. N-sulfate content in the heparan sulfate, however, had no relation to molecular weight, and was 0.33 mole per mole of glucosamine on the average. About 70% of the heparan sulfate with the lowest molecular weight (1,500) were composed of three repeating disaccharide units of heparan sulfate and two acetyl, one N-sulfate and three O-sulfate groups linked to the units. The dermatan sulfate contained 1.0-1.2 moles of sulfate per mole of galactosamine. Of the excess sulfate 45-65% were bound to iduronate residues and the rest to C-6 of N-acetylgalactosamine 4-sulfate residues. Most of the dermatan sulfate (83.2-100%) had nonsulfated iduronic acid at the non-reducing end. This finding is consistent with the defect of iduronidase in this disease.
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PMID:Characteristics of urinary glycosaminoglycans excreted by a patient with the Hurler-Scheie compound syndrome. 680 94

Human intestinal mucins from six subjects with Cystic Fibrosis (CF) and eight subjects without CF were prepared from tissue obtained at surgery (one case) and postmortem. Subjects were not age-matched, but the nonCF mucin was obtained from subjects with ages which bracketed those of the CF subjects. Cesium chloride analytical gradient ultracentrifugation showed that CF mucins were generally denser than nonCF mucins. Sedimentation coefficients were also higher in the CF samples. CF mucins were enriched in fucose, galactose, N-acetylglucosamine and total carbohydrate per mg protein and per oligosaccharide chain (mole/mole GalNAc). Fucose/sialic acid molar ratios were significantly higher in CF mucins, and the average oligosaccharide chain length was approximately three residues greater in CF as compared with nonCF mucins. There was no difference in amino acid profiles or the number of side chains per molecule. The mean sulfate content was higher in the CF mucins but not to a level of significance; however, in the eight mucins, sulfate content correlated positively with total carbohydrate, N-acetylglucosamine and galactose, and therefore increased with oligosaccharide chain length. CF intestinal mucin was therefore denser and more highly glycosylated than nonCF musin and probably contained more sulfate. The increase in glycosylation resulted from a rise in fucose, galactose, and N-acetylglucosamine without a concomitant rise in sialic acid.
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PMID:Human intestinal mucin in cystic fibrosis. 683 17

The sequence in the assembly of the functional unit of selectin ligands containing sulfate, sialic acid, and fucose and also tumor-associated O-glycan structures was studied by examining the specificities of alpha 2,3-sialyltransferases (ST). The first enzyme, porcine liver ST, was 57, 37, and 79% active (Km: 0.105, 0.420, and 0.200 mM), respectively, toward 6-sulfo, 6-sialyl, or 6-O-methyl derivatives of the Gal beta 1,3GalNAc alpha- unit; C-3 or C-6 substitution on Gal abolished sialylation. An acrylamide copolymer (MW approximately 40,000) containing approximately 40 T-haptens and asialo Cowper's gland mucin (MW approximately 200,000) containing approximately 48 T-haptens was 5-fold more active as an acceptor as compared to Gal beta 1, 3GalNAc alpha-O-Al on a molecular weight basis. The second enzyme, a cloned alpha-2,3-ST specific for lactose-based structure, was 70, 102, and 108% active (Km: 0.500, 0.210, and 0.330 mM), respectively, toward 6-sialyl, 6-sulfo, or 6-O-methyl derivatives of the Gal beta 1,3GlcNAc beta- unit; C-3 and C-6 substitution on Gal abolished sialylation. Gal beta 1,4GlcNAc beta- and its 6-sulfo derivative were approximately 20% active; the Lewis a structure, Gal beta 1,3- (Fuc alpha 1,4)GlcNAc beta-, was not an acceptor. The acrylamide copolymers containing approximately 40 units of Gal beta 1,3GlcNAc beta-, Gal beta 1,3(6-sulfo)GlcNAc beta-, or fetuin triantennary asialo or bovine IgG diantennary glycopeptides were respectively 5.9-, 5.4-, 0.7-, and 0.1-fold as active. A transfer of 7-9 mol of NeuAc per mole of the above copolymers was catalyzed by this ST, the sialyl linkage being susceptible to alpha 2,3-specific sialidase. A partially purified Colo 205 Lewis type (alpha 1, 3/4) fucosyltransferase catalyzed the formation of 3'-sialyl-6-sulfo Lewis a from [9-3H]NeuAc alpha 2, 3Gal beta 1, 3(6-sulfo)GlcNAc beta-O-Allyl and copolymer containing [9-3H]NeuAc alpha 2, 3Gal beta 1, 3(6-sulfo)GlcNAc beta- units, using GDP[14C]Fuc as fucosyl donor. The third enzyme, HL-60 ST, was 103% active with Gal beta 3(6-sulfo)GalNAc alpha- but was only 8% active with 6-sialo compound; it showed 11.6-fold greater activity with the copolymer of T-hapten. Further, we observed the alpha 2,3 sialylation of Gal beta 1,4GlcNAc beta- but not Gal beta 1,3GlcNAc beta- by HL60-ST, consistent with the occurrence of 3'-sialyl LacNAc and 3'-sialyl Lewis x units in leukosialin of HL60.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Selectin ligands and tumor-associated carbohydrate structures: specificities of alpha 2,3-sialyltransferases in the assembly of 3'-sialyl-6-sialyl/sulfo Lewis a and x, 3'-sialyl-6'-sulfo Lewis x, and 3'-sialyl-6-sialyl/sulfo blood group T-hapten. 753 77

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