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A library of oligosaccharide probes (neoglycolipids) from N-glycosylated proteins reveals that conglutinin binds to certain complex-type as well as high mannose-type oligosaccharide chains.

This report describes the preparation of a library of oligosaccharide probes (neoglycolipids) from N-glycosylated proteins, characterization of the probes by liquid secondary ion mass spectrometry, and investigation of their reactions with 125I-labeled bovine serum conglutinin by chromatogram binding assays. The results, together with additional binding studies using neoglycolipids derived from purified complex type bi-, tri-, and tetraantennary oligosaccharides from urine, or their glycosidase-treated products, have shown that the combining specificity of conglutinin includes structures not only on high mannose-type oligosaccharides but also on hybrid- and complex-type chains. With high mannose-type oligosaccharides there is increased reactivity from the Man5 to the Man8 structures, indicating a preference for the terminal Man alpha 1-2 sequence. With complex- and hybrid-type oligosaccharides, the requirements for binding are the presence of nonreducing terminal N-acetylglucosamine or mannose residues, but the presence of a bisecting N-acetylglucosamine residue may inhibit binding. From these results it is deduced that the reactivity of conglutinin with the complement glycopeptide iC3b rather than the intact glycoprotein C3 is due to the oligosaccharide accessibility rendered by proteolysis in the complement cascade.

Carbohydrate Conformation↗

The biosynthesis of oligosaccharide-lipids. Isolation of an oligosaccharide-P-P-lipid acceptor.

An oligosaccharide-P-P-lipid has been isolated from porcine liver by extraction with organic solvents and purified by chromatography on silica gel and DEAE-cellulose. The purified oligosaccharide-lipid was shown to contain mannose and N-acetylglucosamine in an approximate ratio of 1:1 and our results suggest that the major oligosaccharide component in the preparation was a tetrasaccharide with the composition (Man)2 (GlcNAc)2. When the oligosaccharide-lipid was incubated with GDP-[14C]mannose and a solubilized enzyme preparation from rabbit liver in the presence of MgCl2, three radioactive products could be isolated. The oligosaccharides in the products could be identified as a penta-, a hexa-, and a heptasaccharide. These products were formed by the stepwise addition of mannose to the growing oligosaccharide chain and GDP-mannose was indicated as the glycosyl donor in each reaction.

Animals↗

Synthesis of the N-linked oligosaccharides of glycoproteins. Assembly of the lipid-linked precursor oligosaccharide and its relation to protein synthesis in vivo.

The asparagine-linked oligosaccharides of chick embryo fibroblast glycoproteins were previously shown to derive from a common lipid-linked precursor, Glc3Man9GlcNAc2. The formation of this precursor oligosaccharide was examined in intact chick embryo fibroblasts, NIL-8 cells, and Chinese hamster ovary cells. The labeling kinetics and compositions of the lipid-linked oligosaccharides were examined, and the results indicate that lipid-linked Man5GlcNAc2 is rapidly assembled (< 1.5 min) and then extended (< 2.5 min) to Glc3Man9GlcNAc2 via the intermediate Man8GlcNAc2. Chain elongation from Man5GlcNAc2- to Man8GlcNAc2-lipid probably occurs by addition of single mannose residues. The pool of lipid-linked Glc3Man9GlcNAc2 turns over with a half-time of 3.5 to 6 min; since there is little if any degradation (the mannose residues do not turn over), this reflects the rate at which completed chains are transferred to acceptor proteins. The same intermediates and similar kinetics were observed in all three cell types. Oligosaccharide-lipid assembly was also examined in cells in which protein synthesis was decreased (using actinomycin D to depress levels of mRNA) or abolished (using cycloheximide). The results indicate that the rate of oligosaccharide-lipid synthesis is proportional to the rate of protein synthesis. The regulated step is prior to the Man5GlcNAc2 stage, and we suggest that the most likely control mechanism is limitation of available oligosaccharide carrier lipid.

Animals↗

Multiple interactions of IgG with its core oligosaccharide can modulate recognition by complement and human Fc gamma receptor I and influence the synthesis of its oligosaccharide chains.

Glycosylation at Asn297 within the CH2 domains of IgG is important for recognition by the effector ligands Fc gammaR and C. Protein engineering has been used to replace amino acid residues within the extensive oligosaccharide interaction site that contact the core hexasaccharide (GlcNAc2Man3GlcNAc). Replacement of residues Phe241, Val264, or Asp265, in particular, results in reduced recognition of human chimeric anti-nitroiodophenacetyl IgG3 produced in Chinese hamster ovary cells, by guinea pig C and human C1q. Replacement of residues Val264 or Asp265, in particular, results in reduced superoxide production triggered through human Fc gammaRI expressed on U937 cells. These results suggest that noncovalent interactions of multiple amino acid residues of IgG with oligosaccharide residues that include the primary and secondary GlcNAc are necessary for optimal recognition of IgG by human Fc gammaRI and C1q. Replacement of residues 241, 243, 264, 265, or 301 with alanine in each case resulted in increased galactosylation and sialylation relative to the wild-type oligosaccharide chains. In particular, for the mutant FA243 there was much increased sialylation of its oligosaccharide chains (73%) relative to the wild-type (4%). Thus, even single residue replacements within the oligosaccharide interaction site of the C region can influence galactosylation and sialylation of its oligosaccharide chains. These data suggest a protein engineering route to the production of more homogeneously glycosylated IgG molecules with or without compromised biologic activities.

Animals↗

Lipo-oligosaccharides of Campylobacter jejuni serotype O:10. Structures of core oligosaccharide regions from a bacterial isolate from a patient with the Miller-Fisher syndrome and from the serotype reference strain.

Lipo-oligosaccharide (LOSa) was obtained by phenol-water extraction of bacterial cells of an isolate PG 836, identified as Campylobacter jejuni serotype O:10, from a patient who subsequently developed the Miller-Fisher syndrome (MFS). The product was separated into a water-insoluble gel of low Mr and a water-soluble component of high Mr. The structure of the core oligosaccharide region in LOSa is reported herein for comparison with LOSb from the C. jejuni O:10 reference strain, and is based on investigations carried out on: (1) O-deacylated LOSa; (2) the core oligosaccharide (OS 1a) liberated on acetic acid hydrolysis of the ketosidic linkages to lipid A, with accompanying loss of N-acetylneuraminic acid residues; (3) the product of the removal of phosphate residues from OS 1a to give OS 2a; and (4) the Smith degradation of OS 2a to yield a mixture of Os 3a and OS 4a. The results revealed that the core oligosaccharide region in LOSa from the MFS bacterial isolate had chains (1a), of which some were terminated by an N-acetylneuraminobiose [Neu5Ac(alpha 2-8)Neu5Ac] unit in a GD3 [Neu5Ac-Neu5Ac-Gal] epitope, and the inner regions of which were different from those of other C. jejuni serotypes. Similar experiments on LOSb from bacterial cells of the C. jejuni O:10 reference strain showed that the core oligosaccharide unit [1a, R = P (phosphoric monoester)] of LOSa from the MFS isolate was more uniformly complete than that of the O:10 reference strain [1b, R = AEP (2-aminoethylphosphate)] differing in the nature of the phosphate substituent at the inner heptose residue. The close structural relationship of LOSa from the MFS associated bacterium to LOSb from the O:10 reference strain runs parallel to that of the previously studied Guillain-Barré syndrome (GBS) associated bacterium typed as C. jejuni O:19 in comparison with the lipo-oligosaccharide from the reference strain. Preliminary studies on the high Mr components showed that those from the O:10 strains were indistinguishable from each other, but were structurally unrelated to those from the GBS associated C. jejuni serotype O:19 isolates and the O:19 reference strain [G.O. Aspinall, A.G. McDonald, and H. Pang, Biochemistry, 33 (1994) 250-255].

Campylobacter jejuni↗

Characterization of the oligosaccharides from lipid-linked oligosaccharides of mung bean seedlings.

Lipid-linked oligosaccharides were synthesized with the particulate enzyme preparation from mung bean (Phaseolus aureus) seedlings in the presence of GDP-[(14)C] mannose. The oligosaccharides were released from the lipids by mild acid hydrolysis and purified by several passages on Biogel P-4 columns. Five different oligosaccharides were purified in this way. Based on their relative elution constants (K(d)) compared to a variety of standard oligosaccharides, they were sized as (mannose-acetylglucosamine) Man(7)GlcNAc(2), Man(5)GlcNAc(2), Man(3)GlcNAc(2), Man(2)GlcNAc(2), and ManGlcNAc(2). These oligosaccharides were treated with endoglucosaminidase H and alpha- and beta-mannosidase, and the products were examined on Biogel P-4 columns. They also were subjected to a number of chemical treatments including analysis of the reducing sugar by NaB(3)H(4) reduction, methylation analysis, and in some cases acetolysis. From these data, the likely structures of these oligosaccharides are as follows: E, Manbeta-GlcNAc-GlcNAc; D, Manalpha1-->3Manbeta-GlcNAc-GlcNAc; C, Manalpha1-->2Manalpha1-->3Manbeta-GlcNAc-GlcNAc; B, Manalpha1-->2Manalpha1-->2Manalpha1--> 3(Manalpha1-->6)Manbeta-GlcNAc-GlcNAc; and A, Manalpha1-->2Manalpha1--> 2Manalpha1-->3(Manalpha1--> [Manalpha1-->6]Manalpha1-->6) Manbeta-GlcNAc-GlcNAc. The synthesis of the Man(7)GlcNAc(2) was greatly diminished when tunicamycin (10 mug/ml) was added to the incubation mixtures.

Journal Article↗

Different oligosaccharides accumulate in the brain and urine of a cat with alpha-mannosidosis: structure determination of five brain-derived and seventeen urinary oligosaccharides.

Five brain-derived and 17 urinary oligomannose-type oligosaccharides were isolated by ion-exchange chromatography on Mono Q or Dowex, followed by HPLC on Lichrosorb-NH2 from a Persian cat suffering from alpha-mannosidosis. The structures of the carbohydrate chains were determined by 500- or 600-MHz 1H-NMR spectroscopy. Different oligosaccharide patterns were found in brain and urine. 99% of the urinary oligosaccharides possess an alpha(1-6)-linked mannose residue attached to beta-mannose, whereas only 5% of the brain-derived oligosaccharides contain such a residue. Furthermore, of the urinary carbohydrate chains 71% end with Man beta 1-4GlcNAc beta 1-4GlcNAc and 29% end with Man beta 1-4GlcNAc, whereas the corresponding amounts are 23% and 77%, respectively, for the brain-derived oligosaccharides.

Animals↗

Biosynthesis of lipid-linked oligosaccharides. I. Preparation of lipid-linked oligosaccharide substrates.

In order to purify the glycosyltransferases involved in the assembly of lipid-linked oligosaccharides and to be able to study the acceptor substrate specificity of these enzymes, methods were developed to prepare and purify a variety of lipid-linked oligosaccharides, differing in the structure of the oligosaccharide moiety. Thus, Man9 (GlcNAc)2-pyrophosphoryl-dolichol was prepared by isolation and enzymatic synthesis using porcine pancreatic microsomes, while Glc3Man9(GlcNAc)2-PP-dolichol was isolated from Madin-Darby canine kidney cells. Treatment of these oligosaccharide lipids with a series of selected glycosidases led to the preparation of Man alpha 1,2Man alpha 1,2Man alpha 1,3[Man alpha 1,6(Man alpha 1,3)Man alpha 1,6]Man beta 1,4GlcNAc beta 1,4GlcNAc-PP-dolichol; Man alpha 1,2Man alpha 1,2Man alpha 1,3[Man alpha 1,6]Man beta 1,4GlcNAc beta 1, 4GlcNac-PP-dolichol; and Man alpha 1,6(Man alpha 1,3)Man alpha 1, 6[Man alpha 1,3]Man beta 1,4GlcNAc-beta 1,4GlcNAc-PP-dolichol. The preparation, isolation, and characterization of each of these lipid-linked oligosaccharide substrates are described.

Animals↗

Hydrolysis of low-molecular-weight oligosaccharides and oligosaccharide alditols by pig intestinal sucrase/isomaltase and glucosidase/maltase.

The ability of purified pig intestinal sucrase/isomaltase (SI; EC 3.2.1.10/48) and glucosidase/maltase (GM; EC 3.2.1.20) to hydrolyze di- and oligosaccharides consisting of D-glucose and D-fructose residues and the corresponding alditols was studied. The products, after incubation, reflect different binding patterns at both catalytic sites of SI. The active site of the sucrase subunit cleaves alpha,beta-(1-->2) glycosidic bonds, and only two monomer units of the substrates bind with favorable affinity. Oligosaccharides and reduced oligosaccharides containing alpha-(1--6) and alpha-(1-->1) glycosidic bonds are hydrolyzed by isomaltase, and for the active site of this subunit more than two subsites were postulated. Moreover, different binding sites for various aglycons seem to exist for isomaltase. Oligosaccharide alcohols are cleaved at lower rates if the reduced sugar residue occupies the aglycon binding site. GM also hydrolyzes alpha-(1-->1) linkages, but at a lower rate. The enzyme has the ability to bind compounds containing residues other than D-glucose. There are indications for similarities between GM and the isomaltase subunit of SI in the binding mode of oligosaccharides.

Animals↗

Cellular effects of deoxynojirimycin analogues: inhibition of N-linked oligosaccharide processing and generation of free glucosylated oligosaccharides.

In the accompanying paper [Mellor, Neville, Harvey, Platt, Dwek and Butters (2004) Biochem. J. 381, 861-866] we treated HL60 cells with N-alk(en)yl-deoxynojirimycin (DNJ) compounds to inhibit glucosphingolipid (GSL) biosynthesis and identified a number of non-GSL-derived, small, free oligosaccharides (FOS) most likely produced due to inhibition of the oligosaccharide-processing enzymes a-glucosidases I and II. When HL60 cells were treated with concentrations of N-alk(en)ylated DNJ analogues that inhibited GSL biosynthesis completely, N-butyl- and N-nonyl-DNJ inhibited endoplasmic reticulum (ER) glucosidases I and II, but octadecyl-DNJ did not, probably due to the lack of ER lumen access for this novel, long-chain derivative. Glucosidase inhibition resulted in the appearance of free Glc1-3Man structures, which is evidence of Golgi glycoprotein endomannosidase processing of oligosaccharides with retained glucose residues. Additional large FOS was also detected in cells following a 16 h treatment with N-butyl- and N-nonyl-DNJ. When these FOS structures (>30, including >20 species not present in control cells) were characterized by enzyme digests and MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS, all were found to be polymannose-type oligosaccharides, of which the majority were glucosylated and had only one reducing terminal GlcNAc (N-acetylglucosamine) residue (FOS-GlcNAc1), demonstrating a cytosolic location. These results support the proposal that the increase in glucosylated FOS results from enzyme-mediated cytosolic cleavage of oligosaccharides from glycoproteins exported from the ER because of misfolding or excessive retention. Importantly, the present study characterizes the cellular properties of DNJs further and demonstrates that side-chain modifications allow selective inhibition of protein and lipid glycosylation pathways. This represents the most detailed characterization of the FOS structures arising from ER a-glucosidase inhibition to date.

1-Deoxynojirimycin↗

The core molecule from type H proteoglycan. Release of mannose-containing oligosaccharides by digestion with N-oligosaccharide glycopeptidase.

Chick-embryo cartilage contains a unique set of proteoglycans. Type H proteoglycan (PG-H) is the most abundant, constituting over 90% of the total cartilage hexuronate. We previously showed that treatment of PG-H with chondroitinase ACII and keratanase yields a protein-enriched core molecule [PG(-CS,KS)] with enzymically modified linkage oligosaccharides of the chondroitin sulphate and keratan sulphate chains. We report here that further treatment of PG(-CS,KS) with pepsin and N-oligosaccharide glycopeptidase (almond glycopeptidase) released four distinct types of mannose-containing oligosaccharide. Two of them were shown to be: (Formula: see text). Of the mannose-containing glycopeptides formed by pepsin digestion, about 40% (as mannose) were resistant to N-oligosaccharide glycopeptidase. Since the resistant fraction was enriched in keratan sulphate remnants, it is suggest that the mannose-containing oligosaccharides in this fraction represent those located in a keratan sulphate-enriched region of PG-H.

Amidohydrolases↗

Interaction of egg-white glycoproteins and their oligosaccharides with the monomer and the hexamer of chicken liver lectin. A multivalent oligosaccharide-combining site exists within the carbohydrate-recognition domain.

Binding of egg-white glycoproteins and their oligosaccharides to hexameric solubilized form of the chicken hepatic lectin and the monomeric soluble fragment containing the carbohydrate-recognition domain has been investigated by several techniques. Ligand blotting revealed significant differences in binding to two forms of the lectin only for glycoproteins bearing multiple N-linked oligosaccharide moieties in their molecule (riboflavin-binding glycoprotein, avidin or ovomucoid). Inhibition studies indicated that inhibitory potency in a series of linear and branched N-acetyl-D-glucosamine-terminated oligosaccharides is critically dependent on the number and spatial arrangement of the terminal monosaccharide residues for both forms of the lectin. Direct binding of 4-hydroxyphenyl-derivatized radioiodinated oligosaccharides measured by equilibrium dialysis and frontal affinity chromatography points to the existence of two N-acetyl-D-glucosamine-combining sites per one subunit of the lectin, as has been recently reported for the rabbit and rat liver lectin [Lee & Lee (1988) Biochem. Biophys. Res. Commun. 155, 1444-1452]. Highly branch (penta-antennary) oligosaccharides interact with more than one subunit of the hexameric form of the lectin and thus resemble the more complex interaction of the whole glycoprotein.

Animals↗

Unusual neutral oligosaccharides in mature Sindbis virus glycoproteins are synthesized from truncated precursor oligosaccharides in Chinese hamster ovary cells.

We have previously demonstrated the presence of unusual small asparaginyl-oligosaccharides [(Man)3GlcNAc2-ASN] in the mature glycoproteins of Sindbis virus released from both wild-type and lectin-resistant Chinese hamster ovary cells, but the mechanism of synthesis of these structures was not determined. Gel filtration and endo-beta-N-acetylglucosaminidase analyses of Pronase-digested glycopeptides from [3H]mannose-labelled Sindbis virus released at different times after infection of a phytohaemagglutinin-resistant line of Chinese hamster ovary cells demonstrated that these small asparaginyl-oligosaccharides were present in similar relative amounts in virus released throughout the virus infection, rather than arising primarily at late times when cytopathic effects were maximal. Similar analyses of pulse-labelled, cell-associated viral glycopeptides suggested that these small oligosaccharides on mature virus glycoprotein resulted from the normal alpha 1,2-mannosidase processing of truncated precursor oligosaccharides (containing five rather than nine mannoses), rather than from aberrant processing or degradation of the full-size precursor oligosaccharides or normal intermediates.

Animals↗

Primary structure of neutral oligosaccharides derived from respiratory-mucus glycoproteins of a patient suffering from bronchiectasis, determined by combination of 500-MHz 1H-NMR spectroscopy and quantitative sugar analysis. 1. Structure of 16 oligosaccharides having the Gal beta(1----3)GalNAc-ol core (type 1) or the Gal beta(1----3)[GlcNAc beta(1----6)]GalNac-ol core (type 2).

Carbohydrate chains of respiratory-mucus glycopeptides from a patient (blood group O) suffering from bronchiectasis with a Kartagener's syndrome have been released by alkaline borohydride treatment. Application of high-performance liquid chromatography using subsequently two silica columns, one bonded with aminopropyl groups and the other with octadecyl groups, afforded 39 neutral fractions; 35 oligosaccharide-alditol structures have been characterized by employing 500-MHz 1H-NMR spectroscopy in conjunction with sugar analysis. Here, 16 oligosaccharide structures, possessing a core consisting of Gal beta(1----3)GalNAc-ol branching through a GlcNAc residue linked beta(1----6) to the GalNAc residue (core type 2 or core type 1, respectively), are described. Ten oligosaccharide-alditols with these types of cores (2, 3, 10a, 14, 7, 11a, 15a, 16a, 12 and 16c) have been identified previously in human bronchial mucins of patients suffering from cystic fibrosis [Lamblin, G., Boersma, A., Lhermitte, M., Roussel, P., Mutsaers, J.H.G.M., Van Halbeek, H. and Vliegenthart, J.F.G. (1984) Eur. J. Biochem. 143, 227-236]. Of the remaining six compounds, one is a partial structure of oligosaccharides previously described: (Formula: see text). The structures 17a and 20 contain the Y determinant, i.e., Fuc alpha(1----2)Gal beta(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----). High-resolution 1H-NMR spectroscopy is able to distinguish whether the Y determinant is beta(1----3) or beta(1----6) linked in such oligosaccharide-alditols.

Bronchiectasis↗

Thin-layer chromatography of urinary neutral oligosaccharides: the detection of blood group-related oligosaccharides and screening for lysosomal storage disease.

We devised an improved technique of thin layer chromatography, which permitted the high resolution of urinary neutral oligosaccharides and the qualitative determination of blood group related oligosaccharides as well as oligosaccharides pathologically secreted in lysosomal storage diseases. This procedure can be used inscreening for disorders associated with abnormal excretion of oligosaccharides, as well as in the purification of oligosaccharides.

ABO Blood-Group System↗

Diversity of oligosaccharide structures on the envelope glycoprotein gp 120 of human immunodeficiency virus 1 from the lymphoblastoid cell line H9. Presence of complex-type oligosaccharides with bisecting N-acetylglucosamine residues.

The N-linked oligosaccharide structures on the envelope glycoprotein gp120 of human immunodeficiency virus 1 derived from chronically infected lymphoblastoid (H9) cells have been investigated by enzymatic microsequencing after release from protein by hydrazinolysis, labeling with NaB3H4, and chromatography on adsorbent columns of Phaseolus vulgaris erythrophytohemagglutinin and Ricinus communis agglutinin (Mr 120,000) and on Bio-Gel P-4. A substantially greater diversity of oligosaccharide structures was detected than among those released by hydrazinolysis from recombinant gp120 produced in Chinese hamster ovary cells and investigated by similar procedures (Mizuochi, T., Spellman, M.W., Larkin, M., Solomon, J., Basa, L.J., and Feizi, T. (1988) Biochem J. 254, 599-603) and among those released by endoglycosidases from virus-derived gp120 isolated from infected H9 cells after metabolic labeling with D-[2-3H]mannose or D-[6-3H]glucosamine (Geyer, H., Holschbach, L., Hunsmann, G., and Schneider, J. (1988) J. Biol. Chem. 263, 11760-11767). In this study, 16% of the oligosaccharides were identified as complex-type bi-, tri-, and tetraantennary sialo-oligosaccharides with bisecting N-acetylglucosamine residues. Such structures were lacking on recombinant gp120 and could not be detected on the metabolically labeled, virus-derived glycoprotein. As in the earlier investigations, complex-type chains lacking bisecting N-acetylglucosamine residues, hybrid-type chains, and a series of high mannose-type structures with 5-9 mannose residues were identified. In addition, an array of complex-type chains having one or more outer chains with beta-galactosyl residues were detected in this study, but with additional substitutions that require further investigation. The number of potential N-glycosylation sites on gp120 is on the order of 20, but the oligosaccharide structures are far more numerous. Thus, the salient conclusion from this and earlier investigations is that alternative structures occur on at least some of the glycosylation sites and that numerous glycosylation variants of this glycoprotein are produced even within a single cell line. Since the glycosylation is the product of host cell glycosyltransferases, an even greater number of glycosylation variants of gp120 are predicted to arise from the heterogeneous cell populations harboring the virus in in vivo infection.

Borohydrides↗

Urinary oligosaccharides of GM1-gangliosidosis. Different excretion patterns of oligosaccharides in the urine of type 1 and type 2 subgroups.

Oligosaccharide patterns obtained by gel filtration of the urine of GM1-gangliosidosis Type 1 patients are quite different from those of GM1-gangliosidosis Type 2. By studies of oligosaccharides in the four major peaks obtained from the Type 1 subgroup using sequential exoglycosidase digestion, methylation analysis, and periodate oxidation, the structures of 15 oligosaccharides: Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6Man beta 1 leads to 4GlcNAc, Man alpha 1 leads to 6(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6[Gal beta 1 leads to 4GlcNAc beta 1 leads to 4(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2)Man alpha 1 leads to 3]Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 6(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2)Man alpha 1 leads to 6(Gal beta 1 leads to 4Glc NAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 6(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2)Man alpha 1 leads to 6[Gal beta 1 leads to 4GlcNAc beta 1 leads to 4(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2)Man alpha 1 leads to 3]Man beta 1 leads to 4GlcNAc, Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6, and 3(Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3 and 6)Man beta 1 leads to 4GlcNAc, (formula see text) were elucidated. The amounts of total oligosaccharides excreted in the urine of the Type 2 subgroup were approximately one-tenth of those of Type 1. Moreover, the last eight oligosaccharides shown above, which have a Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to outer chain, were completely missing in the urine of Type 2.

Carbohydrate Conformation↗

Transfer of oligosaccharide from oligosaccharide pyrophosphoryl dolichol to endogenous acceptor proteins in human breast malignant and normal tissues.

We have prepared dolichylpyrophosphoryl-[14C]-oligosaccharide (Dol-PP-oligosaccharide) from calf thyroid. Microsomal fractions from human breast tissues catalyzed the transfer of labeled oligosaccharide to endogenous acceptor proteins. Malignant tumors showed higher activity of the oligosaccharide transferring enzyme than normal tissue. With kojibiose (Kj), an inhibitor of (Glc3)-glucosidase, an increase in the radioactivity associated with glycoprotein was observed.

Animals↗