Showing papers on "Sialic acid published in 1973"
TL;DR: Observations suggest a metabolic relationship between G7 and either cerebroside or sulphatide, the third most abundant ganglioside on a molar basis, in adult human white matter.
Abstract: — Gangliosides were isolated from purified human myelin in a yield of 62 μg of lipid-bound sialic acid per 100 mg of dry myelin. Sialosylgalactosyl ceramide (G7) was found to be a major component of the ganglioside fraction, amounting to 15 per cent of the total sialic acid. It accounted for 10 per cent of lipid-bound sialic acid in adult human white matter, making it the third most abundant ganglioside on a molar basis. These results were obtained with an improved method for isolating total gangliosides in high yield, by employing DEAE-Sephadex column chromatography. Myelin from other mammalian species had considerably less G7, and there were also indications of maturational changes. Both 2-hydroxy and unsubstituted fatty acids were components of the ceramide unit, in a ratio of 3:2, respectively. The overall fatty acid pattern was very similar to that for myelin cerebroside and sulphatide. Long-chain bases included only C18 species, with sphingosine predominating (>90 per cent). These observations suggest a metabolic relationship between G7 and either cerebroside or sulphatide.
529 citations
Journal Article•
TL;DR: It is suggested that the transformed cell surface—being unable to modulate its expression as a function of the cell cycle in the manner of normal cells—is blocked in a condition of increased sialyl extension resembling that of the normal mitotic cell surface, and thus counteracts functional contract relations between cells.
Abstract: Summary Established lines of malignant (MBVIA) and nonmalignant (MBIII) lymphoblasts, baby hamster kidney cells (BHK21/C13), BHK21/C13 cells transformed by polyoma virus, 3T3 mouse fibroblasts, 3T3 cells transformed by SV40 virus, spontaneously transformed 3T3 cells (3T3-f), rat liver cells (RLC), and Novikoff hepatoma N1S1-67 cells were studied in this investigation. Each homologous pair of proliferating cells was differentially labeled with l-fucose-14C and -3H for detection of increased sialic acid density in glycoprotein components of the transformed cell surface. The change was detectable by the faster elution from Sephadex G-50 or Bio-Gel P-10 of the trypsin- and Pronase-digested material of malignant as compared with nonmalignant cells, and the coincidence of elution profiles following neuraminidase treatment. This change was encountered in all cells studied; the greatest change was in 3T3-f cells and the smallest was in SV40-3T3 cells, in which it could be established only by gel filtration over Bio-Gel P-10. Increased sialylation of glycoprotein components has thus been demonstrated for 3 types of cells, namely, lymphoblast, fibroblast, and epithelioid cells cultured in vitro, and for 3 carcinogenic determinants, namely, viral, chemical, and “spontaneous.” We suggest that the transformed cell surface—being unable to modulate its expression as a function of the cell cycle in the manner of normal cells—is blocked in a condition of increased sialyl extension resembling that of the normal mitotic cell surface, and thus counteracts functional contract relations between cells.
259 citations
Journal Article•
TL;DR: Investigation of the immunogenicity of the E. coli polysaccharide showed that it induced antibody in rabbits after multiple injections but not in human volunteers given one or two injections of 50 µg each.
Abstract: Polysaccharide antigens from Escherichia coli 07:K1(L):NM and group B Neisseria meningitidis have been isolated and purified. Like the meningococcal group B polysaccharide, the sialic acid antigen from E. coli was acidic in nature, was susceptible to neuraminidase degradation and lacked O-acetyl groups. Immunologically these two polysaccharides were indistinguishable in assays of hemagglutination inhibition and they produced lines of identity by immunodiffusion. Investigation of the immunogenicity of the E. coli polysaccharide showed that it induced antibody in rabbits after multiple injections but not in human volunteers given one or two injections of 50 µg each.
189 citations
TL;DR: The results suggest that the plasma membrane of the mitotically active undifferentiated crypt cell and the fetal cell both contain active glycosyl-transferase enzymes and acceptor sites which are glycoproteins with incomplete polysaccharide chains.
179 citations
Journal Article•
146 citations
TL;DR: It is likely that the linkage between galactose and N-acetyl-glucosamine residues is missing from all membrane glycolipids which comprise these two sugars, and all Lewis activity of erythrocytes must be derived from glycolIPids absorbed from blood plasma.
Abstract: Fucose-containing glycolipids with H and B blood group activity as well as sialic acid and glucosamine-containing glycolipid were isolated from human erythrocytes. The sequences and linkages of carbohydrate residues in these glycolipids were determined by partial acid hydrolysis, periodate oxidation and methylation studies. Anomeric linkage were ascribed to those materials on the basis of their optical rotations, infrared spectra, susceptibility to enzymes and immunological activities.
The structures of glycolipid H-I and H-II were respectively fucopyranosyl-α-(1 2)-galacto-pyranosyl-β-(1 4)-2-acetamido-2-deoxy-glucopyranosyl-β-(1 3)-galactopyranosyl-β-(1 4)-glucopyranosyl-β-(1 1)-ceramide; fucopyranosyl-α-(1 2)-galactopyranosyl-β-(1 4)-2-acetamido-2-deoxy-glucopyranosyl-β-(1 3)-galactopyranosyl-β-(1 4)-2-acetamido-2-deoxy-glucopyranosyl-β-(1 3)-galactopyranosyl-β-(1 4)-glucopyranosyl-β-(1 1)-ceramide. The structure of glycolipid B-I was galactopyranosyl-α-(1 3)-[fucopyranosyl-α-(1 2)]-galactopyranosyl-β-(1 4)-2-acetamido-2-deoxy-glucopyranosyl-β-(1 3)-galactopyranosyl-β-(1 4)-glucopyranosyl-β-(1 1)-ceramide. The structure of sialic acid and glucosamine-containing glycolipid was N-acetyl-neuraminosyl-α-(2 3)-galactopyranosyl-β-(1 4)-2-acetamido-2-deoxy-glucopyranosyl-β-(1 3)-galactopyranosyl-β-(1 4)-glucopyranosyl-β-(1 1)-ceramide. The exclusive presence of 4′-galactosyl-N-acetylglucosamine in four erythrocyte glycolipids makes it likely that the (1 3) linkage between galactose and N-acetyl-glucosamine residues is missing from all membrane glycolipids which comprise these two sugars. Therefore the formation of Lea and Leb active structures is not possible in membrane glycolipids and all Lewis activity of erythrocytes must be derived from glycolipids absorbed from blood plasma.
138 citations
TL;DR: It is concluded that dopamine-β-hydroxylase is a tetrameric glycoprotein that contains residues of mannose, glucosamine, galactose, glucose, fucose, and sialic acid.
Abstract: Dopamine-β-hydroxylase (EC 1.14.2.1) has been isolated as a pure protein from bovine-adrenal glands. Although the molecular weight of the native protein is well established (290,000), sodium dodecyl sulfate-gel electrophoresis under dissociating conditions gave a single band with a molecular weight of about 75,000. The enzyme contains about 4% carbohydrate, which consists of residues of mannose, glucosamine, galactose, glucose, fucose, and sialic acid. The pure enzyme also contains about 4 atoms of copper per molecule. It is concluded that dopamine-β-hydroxylase is a tetrameric glycoprotein.
126 citations
TL;DR: The study suggested that sialic acid residues on the cell surface may be specific receptors for TRIC organisms, but not by inactivated lymphogranuloma venereum or influenza virus.
Abstract: The infectivity of trachoma-inclusion conjunctivitis (TRIC) organisms (TW-5) was enhanced by pretreatment of HeLa cell monolayers before inoculation with diethylaminoethyl (DEAE)-dextran (30 μg/ml) and poly-l-lysine (10 μg/ml) and inhibited by dextran sulphate (250 μg/ml), fetuin (4%), ovomucoid (5%), N-acetyl neuraminic acid (0.5%), and Cholera vibrio neuraminidase (100 U/ml). The infectivity of lymphogranuloma venereum organisms (434) was not affected by DEAE-dextran, fetuin, and neuraminidase, was slightly inhibited by poly-l-lysine, and was inhibited by dextran-sulphate, ovomucoid, and N-acetyl neuraminic acid. The study suggested that sialic acid residues on the cell surface may be specific receptors for TRIC organisms. The receptors for TRIC organisms (TW-5 and TW-3) could be specifically blocked with inactivated (56 C for 30 min) TRIC organisms at the ratio of one live to 100 inactivated TRIC organisms, but not by inactivated lymphogranuloma venereum (434) or influenza virus (A2/Jap 305).
102 citations
TL;DR: Glycine N-methyltransferase, an enzyme which methylates glycine in the N-position to yield sarcosine, has been purified to homogeneity from rabbit liver and partially characterized.
90 citations
TL;DR: It is indicated that tumorigenic transformation is accompanied by the appearance of sialidase activity directable toward extracellular lipid-bound sialyl substrate.
86 citations
TL;DR: Fractionation of carcinoembryonic antigen by ECTEOLA-cellulose chromatography and by isoelectric focusing indicated that the antigen was heterogeneous and all fractions were antigenically active and exhibited immunologic identity with respect to one another.
TL;DR: The ovine submaxillary mucin synthesized by the purified enzyme was purified and characterized, and periodate oxidation studies showed that the sialic acid was linked to the N-acetylgalactosamine residue at C-6.
TL;DR: The difference inganglioside composition of synaptosomes and their outer membranes and on the other hand of myelin appears to reflect the difference in gangliosides composition of neuronal and oligodendroglial plasma membranes.
Abstract: — The composition and content of gangliosides from rat-brain microsomal, synaptosomal, mitochondrial and myelin fractions were studied. Outer membranes of synaptosomes were also isolated, separated into subfractions and investigated. Of all the fractions studied the outer membranes of synaptosomes are richest in gangliosides, in one of their sub-fractions the concentration of gangliosides per mg of protein is five times higher than in the homogenate. Microsomes are rich in gangliosides as well, but to a lesser degree, whereas the mitochondrial fraction contains considerably smaller amounts of gangliosides per mg of protein than does the homogenate. The ganglioside pattern of outer membranes of synaptosomes and of their subfractions is somewhat different from that of the homogenate; the outer membranes contain approximately one-third less monosialogangliosides. On the contrary a very high content of monosialogangliosides is characteristic of the ganglioside pattern of the myelin fraction. In this fraction monosialoganglioside GMI (nomenclature of Svennerholm, 1963) constitutes 60–63 per cent of ganglioside sialic acid, or 75–80 molar per cent of gangliosides, the content of di- and trisialogangliosides being much lower than in other fractions. Fatty acid and long chain base composition of gangliosides from synaptosomal and microsomal fractions and homogenate is very similar, almost identical. In gangliosides from myelin fractions the relaitve content of palmitic and monoenoic acids is higher and that of arachinic acid and C20-sphingosine—lower than in other fractions studied. The difference in ganglioside composition of synaptosomes and their outer membranes and on the other hand of myelin appears to reflect the difference in ganglioside composition of neuronal and oligodendroglial plasma membranes.
TL;DR: This work wondered whether a similar mechanism would initiate platelet aggregation by bovine factor VIII, and identified a substrate-enzyme complex formed between side chains of collagen containing galactose but not terminated by sialic acid and sialyl transferase located on the platelet membrane.
Abstract: RECENT work1,2 has demonstrated that bovine factor VIII, not bovine fibrinogen, aggregates human platelets This aggregation can occur in two waves, the first being independent of release of platelet adenosine-5′-diphosphate Bovine factor VIII is rich in carbohydrate: it contains 11% hexoses (mannose and galactose, in a ratio of 1 to 3), 2% sialic acid and 7% hexosamine3 Carbohydrate side chains would play a critical role in collagen–platelet adhesion and subsequent aggregation; a substrate-enzyme complex4 would be formed between side chains of collagen containing galactose5 but not terminated by sialic acid and sialyl transferase located on the platelet membrane6 Oxidation of the galactosyl residues in collagen abolishes platelet aggregation5 We wondered whether a similar mechanism would initiate platelet aggregation by bovine factor VIII
TL;DR: It is concluded that rabbit interferon is a glycoprotein containing the terminal oligosaccharide sequence sialic acid --> galactose, which contains both (3)H and (14)C activity.
Abstract: In an attempt to understand the structure of rabbit interferon, the possibility of carbohydrate being part of the molecule was tested. Interferon incubated with neuraminidase from Vibrio cholera is homogeneous in charge as revealed by isoelectric focusing. Treatment of “asialointerferon” with galactose oxidase (EC 1.1.3.9) from Dactylium dendroides and subsequent reduction with tritiated sodium borohydride yields labeled material with unimpaired antiviral activity. Enzymic incorporation of N-[14C]acetylneuraminic acid into tritiated asialointerferon restores the original charge heterogeneity. The newly generated sialointerferon contains both 3H and 14C activity. Asialointerferon is retained by an affinity column containing phytohemagglutinin from Phaseolus vulgaris and can be displaced from the adsorbent by a glycoprotein of known structure. It is concluded that rabbit interferon is a glycoprotein containing the terminal oligosaccharide sequence sialic acid → galactose.
TL;DR: After intracranial injection of N‐[3H]acetylmannosamine autoradiography showed lipid‐ and non‐lipid‐bound radioactivity in the tectum opticum evenly distributed over regions of nerve fibres or perikarya indicating an ubiquitous incorporation of label, which does not change considerably with the time after injection or the distance from the eye.
Abstract: —The concentration of lipid- and non-lipid-bound sialic acid in the optic nerve tract and tectum and in whole brain of fish was estimated. The incorporation of sialic acid into gangliosides and non-lipid components was studied in fish by intracranial or intraocular application of N-[3H]acetylmannosamine or N-[3H]acetylglucosamine. After intracranial injection of N-[3H]acetylmannosamine autoradiography showed lipid- and non-lipid-bound radioactivity in the tectum opticum evenly distributed over regions of nerve fibres or perikarya indicating an ubiquitous incorporation of label. Sialic acid incorporation into glycoproteins after intracranial injection of N-acetylmannosamine always exceeded that into gangliosides. TCA-precipitable non-lipid material is labelled from intracranially applied N-acetylmannosamine in the sialic acid portion and also in nonsialic acid components, whereby the percentage of label in sialic acid increases reaching 90 per cent of the total radioactivity after 90 min. After intraocular application of N-[3H]acetylmannosamine, sialic acid in gangliosides was generally found to be more highly labelled than in glycoproteins. The ratio of radioactivity in gangliosides and glycoproteins increased with time of incubation and the distance from the eye. TCA-soluble radioactivity was translocated by fast axonal transport. Cycloheximide inhibited incorporation of N-acetylmannosamine-derived radioactivity into gangliosides and proteins but not the transport of TCA-soluble material, which accumulates in the tectum. After intraocular application of N-[3H]acetylglucosamine, TCA-soluble label arrives later in the optic tectum than radioactivity of high molecular weight components. The ratio of lipid to non-lipid-bound radioactivity does not change considerably with the time after injection or the distance from the eye. There was no accumulation of TCA-soluble radioactivity after the inhibition of incorporation into high molecular weight components.
TL;DR: The colostrum enzyme exhibited the following important specificity requirements towards the acceptor: high, rather than low molecular weight substrates were much more effective; the penultimate sugar to which galactose was linked in disaccharides markedly influenced the kinetic parameters (Vmax and Km).
TL;DR: The isolation and purification of new group A-, B- and H-specific substances from human erythrocyte membranes is described and they form high-molecular-weight aggregates in aqueous solution but disaggregate into smaller units in the presence of sodium dodecylsulphate.
Abstract: The isolation and purification of new group A-, B- and H-specific substances from human erythrocyte membranes is described. These substances contain galactose, fucose, glucosamine, sialic acid and amino acid residues. The A-specific substance also contains galactosamine. They contain at most about 2% fatty acids or sphingosine. The substances are serologically active; however, both required combination with phospholipids for development of maximum activity ine haemagglutination inhibition tests. Addition of phospholipids was not required in serological precipitation tests. These blood-group substances may be used to coat group-O or Bombay-Oh red cells, thereby conferring on them A-, B-, or H-activity. They form high-molecular-weight aggregates in aqueous solution but disaggregate into smaller units in the presence of sodium dodecylsulphate.
TL;DR: In this article, the bovine pancreas synthesizes each of two amino acid sequences with and without the addition of galactose and sialic acid to the carbohydrate side chain.
TL;DR: Carcinoembryonic antigen and a related glycoprotein, CCEA-2, have been extracted from human metastatic colonic carcinomas and separated by gel filtration and CEA shows charge heterogeneity which is not due to variation in its overall amino acid composition and which may therefore be due to variations in sialic acid content.
TL;DR: Serological studies confirm most of those of previous investigators but show that the abnormal (A) cells lack both M and N antigens as determined by human reagents.
Abstract: . With the use of endless belt fluid electrophoresis, these studies confirm previous reports of two cell populations in PMFP having different mobilities. Our method shows two clearly separated bands, while with the microelectrophoresis method a distinctly bimodal distribution is reported. The abnormal (A) cells show a 33- to 42-percent reduction in mobility and a 47- to 48-percent reduction in sialic acid as compared with standard cells. The serologically normal (N) cell population, on mixture with standard cells and subjected to electrophoresis, exhibits no increase in streak width indicative of increased electrophoretic heterogeneity. This is consistent with the findings in the preceding report of no serological abnormalities in the (N) cells. Results of hematological studies, red cell isozyme determinations and assays of glycolytic enzymes activity were not significantly different between the two cell populations.
These observations lead us to suggest that the basic abnormality in PMFP (A) cells (Tn transformation) represents a point mutation involving a single genetic step in erythrocyte membrane glycoprotein biosynthesis. A block in the transfer of terminal D-galactose to N-acetylgalactosamine in a substantial proportion of (A) cell heterosaccharides is postulated to be common to all of the serological and biophysical aberrations. This would be consistent with the observed reduction of T, NVG, NHmn (also MHmn), electrostatic charge, sialic acid, and increased ‘saline agglutinability’ in incomplete antisera. The defect in galactose linkage could also leave exposed underlying N-acetylgalactosamines with the consequent manifestation of AHmn, ADB, AHP, NBV and Tn.
TL;DR: While membrane sialic acid is necessary for stimulation of phagocytosis, it may function only as a binding site for the three positively charged residues of the tetrapeptide.
TL;DR: Uptake of both [ 14 C]glucosamine and [ 3 H]fucose into this component was greatly reduced in vitamin A deficiency, and the homogeneity of this peak was confirmed by polyacrylamide gel electrophoresis.
TL;DR: Immunological comparisons by double diffusion show that antisera to the intact hormone or its α subunit cross-react with homologous TSH and with the human gonadotropins but that the antiserum against the β subunit is specific for thyroid-stimulating hormone.
TL;DR: It is suggested that the sialolipid components in the intact cell surface are relatively unavailable to the extracellular action of VC-neuraminidase, and release of sialic acid from intact cells by VC neuraminid enzyme appears to be from surface sialoglycoproteins.
TL;DR: Results suggest that all of the Ca 2+ -binding sites of bovine Factor II reside in the Fragment 1 portion of this factor.
TL;DR: It is postulated that the plasma glycoproteins that are synthesized later in development contain increased amounts of sialic acid and that the observed changes in microheterogeneity of these proteins represent regulation of glycoprotein biosynthesis at the level of carbohydrate attachment.
Abstract: Changes in microheterogeneity of foetal plasma glycoproteins during development of mouse embryos were investigated. Analysis of foetal plasma by polyacrylamide-gel electrophoresis indicated three major zones of proteins: (1) transferrins, (2) α-foetoproteins and (3) albumin. Three transferrins (Tr1, Tr2, Tr3) and five α-foetoproteins (Fp1, Fp2, Fp3, Fp4, Fp5) were resolved. Evidence for the presence of transferrins was the binding of 59Fe to the three electrophoretic variants. By day 15.5 of gestation, there was a marked increase in the more-acidic components (Tr3, Fp4, Fp5) and a decrease in the less-acidic ones (Tr1, Tr2, Fp1, Fp2, Fp3). Treatment of foetal plasma with neuraminidase at this time of development converted the more acidic components into Tr1 and Tr2 and Fp1, Fp2 and Fp3. Furthermore, it was shown that early in development (day 12.5) only the less-acidic components of transferrin and α-foetoprotein were synthesized; at the later time in development (day 14.5) new synthesis of the acidic components of both groups occurred. That these more-acidic components of α-foetoprotein (Fp4, Fp5) were in fact electrophoretic variants of the less-acidic α-foetoproteins was shown by the immunoprecipitation of labelled Fp4 and Fp5 with anti-Fp1, anti-Fp2 and anti-Fp3. From these results it is postulated that the plasma glycoproteins that are synthesized later in development contain increased amounts of sialic acid and that the observed changes in microheterogeneity of these proteins represent regulation of glycoprotein biosynthesis at the level of carbohydrate attachment.
TL;DR: It appeared that cytidine 5′-monophospho-N-acetylneuraminic acid synthetase, at least for the greater part, is a true nuclear enzyme.
Abstract: — The subcellular distribution of cytidine 5′-monophospho-N-acetylneuraminic acid synthetase, which is a key enzyme involved in the biosynthesis of sialo-glycoproteins and gangliosides, was studied in the frontal grey cortex and the corpus callosum of the calf brain. It appeared that the enzyme was highly concentrated in nuclear fractions, which were shown to be relatively pure as evaluated from morphological, enzymic and chemical data. The possibility that the nuclear localization of the enzyme was due to an artifact, as the result of adsorption onto the nuclear membrane or absorption into the nucleus during the homogenization of the tissue, was ruled out completely and so it appeared that cytidine 5′-monophospho-N-acetylneuraminic acid synthetase, at least for the greater part, is a true nuclear enzyme. The subnuclear localization of the enzyme was shown to be in the nuclear sap. Both neuronal and glial cell nuclei contained the enzyme, which makes it very likely that biosynthesis of sialo-glycoproteins and/or gangliosides occurs in neurons as well as in glial cells. The significance of the nuclear localization of the enzyme for the biosynthesis of sialic acid containing macromolecules and the possible regulatory role played by the nucleus in this process are discussed.