Substrate specificity of mammalian endo-beta-N-acetylglucosaminidase: study with the enzyme of rat liver.
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Biomedical subjects
Publications and source records attributed to A Kobata.
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Human lactoferrin contains 2 asparagine-linked sugar chains in 1 molecule. These sugar chains were released as oligosaccharides by hydrazinolysis from two lactoferrin samples of different races. The two oligosaccharide fractions gave exactly the same fractionation pattern upon paper electrophoresis and Bio-Gel P-4 column chromatography after sialidase digestion. A structural study of the oligosaccharides obtained from the two samples by sequential exoglycosidase digestion in combination with methylation analysis also gave the same results indicating that there is no racial difference both in quality and quantity of the sugar chain moiety of lactoferrin. In addition to the two acidic sugar chains, NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlucNAc and Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to 1Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlcNAc, and two novel acidic sugar chains, Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to 2 Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6(GlcNAc and Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlcNAc, were found to occur in human lactoferrin.
The paper electrophoretic pattern of the oligosaccharides released from the plasma membranes of K-562 cells by hydrazinolysis was quite different from that of human erythrocyte membranes. Bio-Gel P-4 column chromatography in combination with sequential exoglycosidase digestion of the neutral oligosaccharide fractions revealed that all those from K-562 cells are of the high mannose type, while those from erythrocytes are of large complex type structures. Studies of the acidic oligosaccharides indicated that none of those obtained from K-562 cells contained the beta-N-acetylglucosamine residue linked at the C-4 position of the beta-mannosyl residue of the trimannosyl core, which occurs in most of the asparagine-linked sugar chains of human erythrocytes. This indicates that the glucosaminyltransferase that forms the GlcNAc beta 1 leads to 4Man beta 1 leads to group has not been expressed in K-562 cells.
Human fibrinogen contains four asparagine-linked sugar chains in one molecule. All B beta and gamma subunits obtained from both normal fibrinogen and abnormal fibrinogen Nagoya contain 1 mol each of an asparagine-linked sugar chain. The sugar chains were quantitatively liberated as radioactive oligosaccharides from the polypeptide portion by hydrazinolysis followed by N-acetylation and NaB3H4 reduction. By the combination of sequential exoglycosidase digestion and methylation analysis, the structures of the sugar chains of human fibrinogen were elucidated to be NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNac beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc and Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc. Neither quantitative nor qualitative differences were found between the sugar chain moieties of normal fibrinogen and fibrinogen Nagoya, indicating that the molecular basis of the abnormality in the latter may reside in its polypeptide moieties.
Oligosaccharide patterns obtained from human IgG by hydrazinolysis were fairly constant from sample to sample. In contrast, a variety of oligosaccharide patterns were obtained from IgG myeloma proteins. Structural analysis of each oligosaccharide by sequential exoglycosidase digestion and methylation studied indicated that the different patterns of IgG myeloma proteins are produced by different degrees of incompleteness of the formation of a single sugar chain: Sia alpha 2 leads to Gal beta 1 leads to 4GlcNAc beta 1 leads to 2 Man alpha 1 leads to 6(Sia alpha 2 leads to Gal beta 1 leads to 4GlcNAc beta 1 leads to Man alpha 1 leads to 3)(GlcNAc beta 1 leads to 4)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlcNAcOT.
In order to elucidate whether chromosomal change or induction of differentiation is correlated with the change of the patterns of cell surface glycoproteins and asparagine-linked sugar chains, glycoproteins and carbohydrates of five rat erythroleukemic cell lines (K1DB, D5A1, K2D, K2DA, and K4D) were studied by sodium dodecyl sulfate:polyacrylamide gel electrophoresis and hydrazinolysis followed by gel chromatography, respectively. The surface glycoprotein patterns of five cell lines were very similar, each containing four glycoproteins with molecular weights of 250,000, 115,000, 80,000, and 28,000, respectively. Only D5A1, which can be induced to erythroid differentiation, had two additional glycoproteins, with molecular weights of 135,000 and 65,000, respectively. All neutral oligosaccharides obtained from plasma membranes of five cell lines by hydrazinolysis were of the high-mannose type, and the acidic oligosaccharides were of the complex type with three different types of outer chains in various combinations: +/- NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc; Gal beta 1 leads to 3Gal beta 1 leads to 4GlcNAc; and Gal beta 1 leads to 4GlcNac beta 1 leads to 3Gal beta 1 leads to 4GlcNAc. An interesting finding was that two sugar chains, NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3(Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(+/-Fuc alpha 1 leads to 6)GlcNAcOT (in which the subscript OT indicates a NaB3H4-reduced oligosaccharide), were found only in surface carbohydrates of D5A1.
Among the seven oligosaccharide fractions obtained by Bio-Gel P-4 column chromatography of urine of GM1-gangliosidosis Type 1 patients, three fractions (peaks V, VI, and VII) were completely missing in the urine of GM1-gangliosidosis Type 2 patients. Structural study of these oligosaccharide fractions by sequential exoglycosidase digestion in combination with methylation analysis and periodate oxidation has shown that peaks V, VI, and VII are mixtures of 16, 30, and 49 isomeric oligosaccharides. All these 95 oligosaccharides contain Gal beta 1 leads to 4GlcNAc beta 1 lead to 3 repeating structures in their outer chain moieties, indicating that the tissues of GM1-gangliosidosis Type 2 patients do contain beta-galactosidase activity which releases readily galactose residue from such repeating sugar chains.
Rat and human alpha 1-acid glycoproteins contain 5 and 6 acidic asparagine-linked sugar chains in 1 molecule, respectively. The structures of these sugar chains were studied by sequential exoglycosidase digestion in combination with methylation analysis after being released from the polypeptide back bone by hydrazinolysis. All oligosaccharides obtained from both glycoproteins contain N-acetylneuraminic acid. Sialidase digestion of the acidic oligosaccharides from rat sample released three biantennary complex type sugar chains and three triantennary complex type sugar chains, the outer chains of which are composed of Gal beta 1 leads to 3GlcNAc and/or Gal beta 1 leads to 4GlcNAc. In the original acidic oligosaccharides, sialic acids occur as three type linkages: NeuAc alpha 2 leads to 3Gal, NeuAc alpha 2 leads to 6Gal, and Gal beta 1 leads to 3(NeuAc alpha 2 leads to 6)GlcNAc. In addition to the five sugar chains reported by Fournet, B., Montreuil, J., Strecker, G., Dorland, L., Haverkamp, J., Vilegenthart, J. F. G., Binette, J. P., and Schmid, K. ((1978) Biochemistry 17, 5206-5214), the structures of three new sugar chains of human alpha 1-acid glycoprotein were elucidated.
The carbohydrate structures of two membrane glycoproteins (HANA protein and F protein) of HVJ have been determined on materials purified from virions grown in the allantoic sac of embryonated chicken eggs. Both glycoproteins contain fucose, mannose, galactose, and glucosamine but not galactosamine, indicating that their sugar chains are exclusively of the asparagine-linked type. The radioactive oligosaccharide fractions obtained from the two glycoproteins by hydrazinolysis followed by NaB[3H]4 reduction gave quite distinct fractionation patterns after paper electrophoresis. More than 75% of the oligosaccharides from F protein were acidic and separated into at least four components by paper electrophoresis. Only 18% of the oligosaccharide from HANA protein was an acidic single component. These acidic oligosaccharides could not be converted to neutral oligosaccharides by sialidase digestion. Structural studies of the neutral oligosaccharide fractions from HANA and F proteins revealed that both of them are mixtures of a series of high mannose type oligosaccharides and of complex type oligosaccharides with Gal beta 1 leads to (Fuc alpha 1 leads to 3) GlcNAc group in their outer chain moieties.
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.
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The structures of the oligosaccharides released from human ceruloplasmin by hydrazinolysis were studied by sequential exoglycosidase digestion in combination with methylation analysis and periodate oxidation. A molecule of ceruloplasmin was shown to have two biantennary oligosaccharides A-1 and one triantennary oligosaccharide A-2, the structures of which are shown below. (Formula see text) The abbreviations used are: NeuAc, N-acetylneuraminic acid; Gal, galactose; GlcNAc, N-acetylglucosamine; Man, mannose.
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