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At least 19 recordsLinked to original sources
PubMed1979

Purification and properties of N-acetylgalactosamine 6-sulphate sulphatase from human placenta.

1. N-Acetylgalactosamine 6-sulphate sulphatase was purified about 20000-fold from the soluble extract of human placenta with N-acetylgalactosamine 6-sulphate-glucuronic acid-N-acetyl[1-(3)H]galactosaminitol 6-sulphate as substrate in the activity assay. The enzyme appears to be a glycoprotein with a mol.wt. of about 100000 as determined by gel filtration. On gel electrophoresis in the presence of sodium dodecyl sulphate the major protein band had a mol.wt. of 78000. Variable charge heterogeneity was observed in several enzyme preparations. 2. The purified enzyme released up to one sulphate molecule from the disulphated trisaccharide. It was active towards N-acetylgalactosamine 6-sulphate and exhibited no measurable N-acetylglucosamine 6-sulphate sulphatase or any other known lysosomal sulphatase activity. Hydrolysis of [1-(3)H]galactitol 6-sulphate was achieved by incubation neither with a crude nor with a purified enzyme preparation. Chondroitin 6-sulphate and keratan sulphate, as well as heparin and heparan sulphate, served as competitive inhibitors of the enzyme. 3. Purified N-acetylgalactosamine 6-sulphate sulphatase activity was optimal at pH4.9 and 4.4 when assayed in 0.02m-sodium acetate buffer and at pH4.2 and 5.2 in 0.1m-sodium acetate buffer. A single pH-optimum at pH4.8 was observed for the crude enzyme and for the purified enzyme after mild periodate treatment. The sulphatase activity was inhibited by a variety of anions and cations and activated by thiol-specific and thiol reagents.

Chondroitinases and Chondroitin Lyases↗
PubMed1979

The occurrence of uridine diphosphate N-acetylgalactosamine 6-sulfate in quail egg white and characteristic distribution of sulfated sugar nucleotides in different avian eggs.

A sulfated sugar nucleotide has been isolated from quail egg white, and accounts for nearly 80% of the total sugar nucleotides found in the egg white. Evidence is presented that this nucleotide is uridine diphosphate N-acetylgalactosamine 6-sulfate, an isomer of the 4-sulfated derivative of uridine diphosphate N-acetylgalactosamine previously found in chicken egg white. Further studies on the distribution of sulfated sugar nucleotides in egg white of various birds (chicken, quail, pheasant, peafowl, turkey, goose, and duck) demonstrate that each species has a characteristic composition, differing from one another regarding the relative amounts of 4-sulfated, 6-sulfated, and 4,6-bissulfated derivatives of uridine diphosphate N-acetylgalactosamine.

Animals↗
PubMed1975

[Do immunization of rabbits by N-acetylgalactosamine and a disaccharide linked to a protein produce anti-microbial antibodies (author's transl)].

Rabbits were immunized with N-acetylgalactosamine linked to bovalbumine. They produced antibodies which precipitated this same sugar linked to human gamma-globulins but did not agglutinate Salmonella johannesburg which carry a side chain of N-acetylgalactosamine. The same immunization enhanced the titre of "natural" antibodies agglutinating human A red cells (which carry a terminal N-acetylgalactosamine) but they did not evoke such antibodies in rabbits with no "natural" hemagglutinins. These negative results, when compared to the positive one obtained with 0-acetyl-3,6-dideoxygalactose suggest that rabbit antibody-sites limited to one sugar may exist but that they can be detected only under certain conditions. Another group of 8 rabbits was immunized with a disaccharide alpha-Glc-(1 leads to 6)-GalNAc linked to a protein. All produced antibodies agglutinating S. johannesburg (1,40) which carry this disaccharide and S. senftenberg which carry the disaccharide alpha-Glc-(1 leads to 6)-Gal. The titres of these antibodies decreased after a second course of immunization.

ABO Blood-Group System↗
PubMed1977

Solubilization and partial characterization of UDP-N-acetylgalactosamine: globoside alpha-N-acetylgalactosaminyltransferase from dog spleen microsomes.

UDP-N-acetylgalactosamine:globoside alpha-N-acetylgalactosaminyltransferase (EC 2.4.1.-) synthesizing Forssman hapten was solubilized from dog spleen microsomes by a combination of Triton X-100 treatment and sonication. The solubilized enzyme was partially purified by calcium phosphate gel, ammonium sulfate fractionation and then DEAE-cellulose column chromatography. The enzymatic activity of the purified preparation was stimulated by exogenously added phosphatidylserine, as found in the particulate enzyme. When the properties of the purified enzyme were examined in the presence of exogenous phosphatidylserine, the enzyme had an absolute requirement for Mn2+; this was not substituted by Ca2+ or Mg2+. Apparent Km values for UDP-N-acetylgalactosamine and globoside were 1-10(-5) and 5-10(-4) M, respectively. It had a pH optimum of 6.55 regardless of the presence or absence of exogenous lipids. Since the partially purified enzyme was completely free of uridine diphosphatase which was found in the particulate preparaton, the effect of UDP on the transferase activity could be studied. Thus, UDP inhibited 85% of the activity at a concentration of 1.5 mM. p-Cholormercuribenzoate inhibited over 90% of the activity at 2 mM, indicating the transferase to be SH-enzyme.

Animals↗
PubMed2026

Molecular Mobility of N-Acetylgalactosamine-Modified Cyclodextrins on a Polyrotaxane for Highly Efficient Liver Targeting of Antibody Chimeras and Genome-Editing Ribonucleoproteins.

Triantennary N-acetylgalactosamine (triGalNAc), which interacts strongly with the trimeric structure of asialoglycoprotein receptors (ASGPRs), is a validated platform for liver targeting. However, the intricate design and synthesis of its linkers impose high production costs and significant technical challenges. In this study, we report an alternative strategy for targeting ASGPR using monovalent GalNAc (monoGalNAc) conjugated to the cyclic molecules of polyrotaxane, which can rotate and translocate along the axial polymer chain. The intracellular uptake efficacy of monoGalNAc-modified polyrotaxane is comparable to that of triGalNAc-modified polyrotaxane and significantly higher than that of triGalNAc- or monoGalNAc-modified immobile control polymers. These results suggest that the inherent mobility of polyrotaxanes allows monoGalNAc moieties to cluster in a trivalent-like manner, thereby enhancing multivalent interactions with multiple ASGPR oligomers. The successful application of monoGalNAc-modified polyrotaxane to lysosome-targeting antibody chimeras and genome-editing nanoparticles demonstrates that this facile technology is a highly promising alternative to conventional triGalNAc.

Rotaxanes↗
PubMed1979

Gangliosides of human erythrocytes. A novel ganglioside with a unique N-acetylneuraminosyl-(2 leads to 3)-N-acetylgalactosamine structure.

A novel ganglioside having both N-acetylgalactosamine and N-acetylglucosamine was isolated from human erythrocyte membranes. Its structure was characterized by successive exoglycosidase treatment, methylation analysis, and direct-probe mass spectrometry of permethylated intact and desialylated glycolipid. The core structure of the ganglioside was found to be N-acetylgalactosaminyl paragloboside with sialosyl substitution by 2 leads to 3 linkage at the terminal GalNAc residue: NeuNAc alpha 2 leads to 3 GalNAc beta 1 leads to -3Gal beta 1 leads to 4 GlcNAc beta 1 leads to 3 Gal beta 1 leads to 4Glc leads to Cer. The ganglioside was characterized by the presence of a ceramide with myristic acid as the major component.

Acetylgalactosamine↗
PubMed1977

Myxospore coat synthesis in Myxococcus xanthus: enzymes associated with uridine 5'-diphosphate-N-acetylgalactosamine formation during myxospore development.

Activities of the enzymes glutamine synthetase (EC 6.3.1.2.), glucosamine 6-phosphate acetyltransferase (EC 2.3.1.4.), uridine 5'-diphosphate (UDP)-N-acetylglucosamine pyrophosphorylase (EC 2.7.23.), UDP-N-acetylglucosamine 4-epimerase (EC 5.1.3.7.), fructose 1,6-diphosphate phosphatase (EC 3.13.11.), L-glutamine-fructose 6-phosphate transamidase (EC 5.3.1.19.), alkaline phosphatase (EC 3.1.3.1.), and malic dehydrogenase (EC 1.1.1.37) were assayed in partially purified extracts prepared at different stages of myxospore formation and germination in liquid cultures of Myxococcus xanthus. The specific activities of the first six of these enzymes increased 4.5- to 7.5-fold after 2 h of induction with 0.5 M glycerol or 0.2 M dimethyl sulfoxide. The increase in specific activities of these six enzymes was not observed in a mutant unable to be induced with glycerol. During the first 2 to 4 h of induction and during the first hour of germination, the level of these enzymes decreased to the level characteristic of vegetative cells. It is suggested that the six enzymes are responsible for the increased conversion of fructose 1,6-diphosphate to UDP-N-acetylgalactosamine, the major precursor of the myxospore coat.

Acetylglucosamine↗
PubMed1978

Enzymatic formation of UDP-N-acetylgalactosamine in epiphysial-plate cartilage.

The activity of UDP-N-acetylglucosamine 4'-epimerase (EC 5.1.3.7) from newborn pig epiphysial-plate cartilage was investigated. The formation of radioactive UDP-N-acetylgalactosamine from UDP-N-acetyl[U-14C]-glucosamine was demonstrated by radioautography, after hydrolysis of UDP-derivatives and separation of the hexosamines by paper chromatography. The pH optimum and the Km values for UDP-N-acetylglucosamine and NAD were determined. At equilibrium, the ratio UDP-N-acetylglucosamine/UDP-N-acetylgalactosamine reaches a value of about 2.3. The effect of UDP-xylose and UDP-glucuronic acid on the enzyme activity was investigated. NADH inhibits UDP-N-acetylglucosamine 4'-epimerase activity. The inhibitory effect of NADH seems to be strikingly correlated with the value of NAD/NADH ratio and pH.

Animals↗
PubMed1979

Hybrid glycosaminoglycans synthesized by monolayers of chick embryo arterial fibroblasts.

Monolayer cultures of arterial fibroblasts from 13-day chick embryonic aorta incorporated 35SO42- into glycosaminoglycans containing both glucuronic and iduronic acids. Bacterial chondroitinase ABC converted more than 98% of the 35SO4-labeled polymer to mono- or disaccharides, including (1) N-acetyl-D-galactosamine 4-sulfate, (2) delta 4,5-glucuronic acid 2- or 3-sulfate leads to N-acetylgalactosamine 6-sulfate, and (3) the unsaturated disaccharides normally obtained from chondroitin 4-sulfate and chondroitin 6-sulfate sequences. Chondroitinase AC converted only 77% of the 35SO4-labeled polymer to the same mono- and disaccharides and yielded, in addition, the following oligosaccharide products: (1) delta 4,5-glucuronic acid leads to N-acetylgalactosamine 4- or 6-sulfate leads to iduronic acid leads to N-acetylgalactosamine 6- or 4-sulfate; (2) N-acetylgalactosamine 4-sulfate leads to iduronic acid 2- or 3-sulfate leads to N-acetylgalactosamine 6-sulfate; (3) delta 4,5-glucuronic acid leads to N-acetylgalactosamine 4-sulfate leads to (iduronic acid leads to N-acetylgalactosamine 4-sulfate)2; (4) delta 4,5-glucuronic acid leads to N-acetylgalactosamine 4- or 6-sulfate leads to (iduronic acid leads to N-acetylgalactosamine 6- or 4-sulfate)2; (5) higher oligosaccharides containing iduronic acid and N-acetylgalactosamine 4-sulfate.

Animals↗
PubMed1979

The effect of tunicamycin on the glycosylation of lactating-rabbit mammary glycoproteins.

1. Tunicamycin inhibited the incorporation of d-[2-(3)H]mannose into dolichol-linked oligosaccharide and glycoprotein of lactating-rabbit mammary explants by approximately the same extent (approx. 30% of control value), suggesting that lipid-linked intermediates are involved in the mannosylation of mammary glycoproteins. 2. The incorporation of radioactivity from N-acetyl-d-[1-(14)C]glucosamine into dolichol-linked oligosaccharide was inhibited by tunicamycin to 32% of the control value, whereas the incorporation of the radiolabel into glycoprotein was only inhibited to 72% of the control value. 3. Considerable redistribution of label from N-acetylglucosamine to N-acetylgalactosamine was found to occur in the explants. In the presence of tunicamycin approx. 76% of the radioactivity incorporated into glycoprotein from N-acetyl-d-[1-(14)C]glucosamine was present as N-acetylgalactosamine, compared with approx. 61% in the absence of the inhibitor. Thus tunicamycin selectively inhibits the incorporation of N-acetylglucosamine into glycoprotein. 4. Radioactivity from N-acetyl-d-[1-(14)C]glucosamine was incorporated into a glycoprotein that was identified as casein by the use of a casein-specific antiserum, and also into a group of glycopolypeptides with apparent mol.wts. ranging between 40000 and 80000. N-Acetylgalactosamine was the only radioactive sugar released on strong-acid hydrolysis of the immunoprecipitated casein, whereas N-acetylglucosamine was the major radioactive residue present in the non-casein glycoproteins. Glucosamine and galactosamine were the only radiolabelled sugars detected by paper chromatography of the strong-acid hydrolysate of the protein fraction. 5. Tunicamycin inhibited the incorporation of radioactivity from N-acetyl-d-[1-(14)C]glucosamine into the glycopolypeptides with mol.wts. between 40000 and 80000 as described by polyacrylamide-gel electrophoresis, but did not affect the incorporation of label into casein. It appears that tunicamycin inhibits the incorporation of mannose and N-acetylglucosamine into a number of mammary glycoproteins by inhibiting the formation of lipid-linked intermediates, but does not inhibit the incorporation of N-acetylgalactosamine into casein.

Acetylgalactosamine↗
PubMed1977

Biochemical investigations of retinotectal adhesive specificity.

The preferential adhesion of chick neural retina cells to surfaces of intact optic tecta has been investigated biochemically. The study uses a collection assay in which single cells from either dorsal or ventral halves of neural retain adhere preferentially to ventral or dorsal halves of optic tecta respectively. The data presented support the following conclusions: (a) The adhesion of ventral retina to dorsal tecta seems to depend on proteins located on ventral retina and on terminal beta-N-acetylgalactosamine residues on dorsal tecta. (b) The adhesion of dorsal retina to ventral tecta seems to depend on proteins located on ventral tecta and on terminal beta- N-acetylgalactosamine residues on dorsal retina. (c) A double gradient model for retinotectal adhesion along the dorsoventral axis is consistent with the data presented. The model utilizes only two complementary molecules. The molecule suggested to be concentrated dorsally in both retina and tectum seems to require terminal beta-N-acetylgalactosamine residues for adhesion. Its activity is not affected by protease. A molecule fitting these qualifications, the ganglioside GM(2), could not be detected in a gradient, but lecithin vesicles containing GM(2) adhered preferentially to ventral tectal surfaces. The second molecule, concentrated ventrally in both retina and tectum, is a protein and seems capable of binding terminal beta-N- acetylgalactosamine residues. One enzyme, UDP-galactose:GM(2) galactosyltransferase, has been found to be more concentrated in ventral retina than dorsal, but only by 30 percent.

Acetylgalactosamine↗
PubMed1979

A pathway of polygalactosamine formation in Aspergillus parasiticus: enzymatic deacetylation of N-acetylated polygalactosamine.

1. An enzyme which hydrolyzes the acetamido groups of N-acetylgalactosamine residues in N-acetylated polygalactosamine was found in the supernatant fraction of Aspergillus parasiticus AHU 7165, a polygalactosamine-producing strain. 2. N-Acetylated polygalactosamine was used as a substrate in the purification and characterization of this enzyme. A 140-fold purification was obtained by means of ammonium sulfate fractionation followed by chromatography on carboxymethylcellulose and DEAE-cellulose. 3. The enzyme releases about 60-70% of the acetyl groups of N-acetylated polygalactosamine, giving a product with free amino groups. Whereas the enzyme also deacetylates oligosaccharides with 14 or more N-acetylgalactosamine units at a rate similar to that of deacetylation of the polymer, it deacetylates shorter oligosaccharides (trimer to hexamer of N-acetylgalactosamine) much more slowly and is virtually inactive toward disaccharide. Deacetylation can not be detected with bacterial cell wall peptidoglycan, N-acetylated heparin, partially O-hydroxyethylated chitin or monomeric N-acetylgalactosamine derivatives as substrates. 4. This enzyme shows double pH optima of 5.3 and 9.3. The Km value for N-acetylated poly-galactosamine is 0.15 g/l (or 0.54 mM with respect to monosaccharide residues). 5. The occurrence of this enzyme may account for the formation of polygalactosamine with free amino groups.

Acetylgalactosamine↗
PubMed1979

Production of monoclonal antibodies specific for two distinct steric portions of the glycolipid ganglio-N-triosylceramide (asialo GM2).

Two hybrid cell lines were prepared by the fusion of mouse myeloma cells with the spleen cells of BALB/c mice that had been immunized with the glycolipid ganglio-N-triosylceramide (asialo GM2). The specificity of the monoclonal antibodies produced by these hybridomas, one an IgM and the other an IgG3, has been defined by hemagglutination inhibition, complement fixation, and lysis of glycolipid liposomes by antibody and complement. A major determinant recognized by the IgM antibody is the nonreducing terminal N-acetylgalactosamine including the C6 primary hydroxyl group, but excluding the C2-acetamide group of N-acetylgalactosamine, because oxidation with galactose oxidase produced a structure showing only minimal cross-reaction with the IgM but replacement of the N-acetyl group with an N-n-butyryl group produced a glycolipid that reacts with IgM antibody to the same extent as with the unmodified glycoplipd. A major determinant recognized by the IgG3 antibody is the terminal N-acetylgalactosamine including the C2-acetamido group, but excluding the C6 primary hydroxyl group of N-acetylgalactosamine, because replacement of the N-acetyl group with an N-n-butyryl group produced a glycolipid that did not react with the IgG3 antibody; in striking contrast the IgG3 antibody reacted with the C6-oxidized glycolipid as well as with the native glycolipid. Neither antibody reacted significantly with any other natural glycolipids tested including several that are structurally related to asialo GM2 such as ganglioside GM2, ganglio-N-tetraosylceramide (asialo GM1), or ceramide dihexoside. These results indicated that in addition to the fine structure specificity described above both antibodies recognize the nonreducing terminal GalNAc beta 1 leads to 4Gal structure. The strict antigenic specificity of these monoclonal anti-glycolipid antibodies indicates their great potential as specific probes for cell surface studies.

Animals↗
PubMed1979

Structural studies on the carbohydrate units of armadillo submandibular glycoprotein.

The structure of carbohydrate units of the major glycoprotein fraction of armadillo submandibular gland was investigated. Alkaline borohydride reductive cleavage of the glycoprotein resulted in the release of O-glycosidically linked mono- and disaccharide units. The monosaccharide was identified as N-acetylgalactosaminitol, whereas disaccharide contained of N-acetylneuraminic acid and N-acetylgalactosaminitol. Treatment of the native and desialyzed glycoprotein with alpha-N-acetylgalactosaminidase resulted in the removal of 60% and 96% of N-acetylgalactosamine, respectively. No cleavage of this sugar was affected by the action of beta-N-acetylhexosaminidase. Both N-acetylgalactosamine and N-acetylneuraminic acid were susceptible to oxidation with periodate. Analyses of the partially methylated N-acetylgalactosamine derivatives, obtained from the permethylated native glycoprotein, showed the presence of 3,4,6-tri-O-methyl-N-methylacetamidogalactose and 3,4-di-O-methyl-N-methylacetamidogalactose in a ratio of 1 : 0.4. Only 3,4,6-tri-O-methyl-N-methylacetamidogalactose was found in the hydrolysates of permethylated desialyzed glycoprotein. These results together with our previous data on chemical composition of the glycoprotein suggest that about 30% of the oligosaccharide chains consist of NeuAc alpha 2 leads to 6GalNAc alpha 1 leads to O-Thr(Ser) and 70% of GalNAc alpha leads to O-Thr(Ser).

Animals↗
PubMed1978

A sensitive procedure for the diagnosis of N-acetyl-galactosamine-6-sulfate sulfatase deficiency in classical Morquio's disease.

The trisaccharide 6-sulfo-N-acetylgalactosamine-glucuronic acid-6-sulfo-N-acetyl-[1-3H]galactosaminitol was used as a substrate for the determination of N-acetylgalactosamine-6-sulfate sulfatase activity. The amount of liberated sulfate was measured indirectly by separating monosulfated reaction products from the substrate on Dowex 1 X 2 microcolumns in a simple two step procedure. Fibroblast homogenates from patients with various genotypes, except classical Morquio's disease, released 410 +/- 90 pmol sulfate/h/mg cell protein. The enzyme exhibited a pH optimum of pH 4.8 and a KM of about 1 X 10(-4) mol/1. It was strongly inhibited by phosphate, sulfate and chloride ions. In three cell lines from patients with classical Morquio's disease a residual activity between 1 and 2% of the mean normal activity was found. All cell lines tested released sulfate from 6-sulfo-N-acetylglucosamine-glucuronic acid-[1-3H]-anhydromannitol. Cell extracts from cultured amniotic fluid cells exhibited a N-acetylgalactosamine-6-sulfate sulfatase activity between 120 and 320 pmol/h/mg protein. An enzyme activity of 370 +/- 100 pmol sulfate/h/mg protein was found in peripheral leucocytes from healthy donors. The determination of N-acetyl-galactosamine-6-sulfate sulfatase activity in one family with an affected patient indicated that the enzyme deficiency is also expressed in leucocytes.

Amniotic Fluid↗
PubMed1979

Enzymic O-glycosylation of synthetic peptides from sequences in basic myelin protein.

Nine synthetic peptides containing sequences in the region of a threonine residue at position 98 of bovine basic myelin protein were prepared by the Merrifield solid-phase method and tested for their ability to be glycosylated with [14C]uridinediphospho-N-acetylgalactosamine and a crude detergent-solubilized preparation of uridinediphospho-N-acetylgalactosamine:mucin polypeptide N-acetylgalactosaminyltransferase obtained from porcine submaxillary glands. The tetrapeptide Thr-Pro-Pro-Pro and all larger peptides containing this sequence were glycosylated. The glycosylation was greater for peptides containing residues N-terminal to the Thr-Pro-Pro-Pro. Under the conditions used, the peptide Val-Thr-Pro-Arg-Thr-Pro-Pro-Pro was glycoslyated twice as much as bovine basic myelin protein. Thr-Pro and Thr-Pro-Pro, as well as 10 other synthetic peptides which did not contain the Thr-Pro-Pro-Pro sequence, were not glycosylated. Treatment of the glycopeptide of Phe-Lys-Asn-Leu-Val-Thr-Pro-Arg-Thr-Pro-Pro-Pro-Ser with an alpha-N-acetylgalactosaminidase released N-acetylgalactosamine from the peptide, indicating that the hexosamine was covalently bonded to the peptide in an alpha linkage.

Amino Acid Sequence↗