Showing papers on "Sialic acid published in 1971"
TL;DR: Evidence is presented to indicate a generalized role for the terminal sialic acid residues of circulating glycoproteins of desialylated plasma proteins inducers of gonadotropic hormones and follicle-stimulating hormone.
1,036 citations
TL;DR: The periodate-resorcinol method was substantially more sensitive than the resorcinl procedure, was not affected by lipids, amino acids, or sugars, and could be used to detect free or glycosidically bound sialic acids on paper chromatograms.
969 citations
Book•
28 Jun 1971
TL;DR: The species specificity which had been observed in rat and human transcortin for the species specific corticosteroid has not been found to be a general phenomenon.
Abstract: : The species specificity which had been observed in rat and human transcortin for the species specific corticosteroid has not been found to be a general phenomenon. The corticosteroidbinding proteins in the sera of various mammalian species belong to the alpha gloublin as was demonstrated by the method of equilibrium paper electrophoresis. Electrophoretic studies showed that the transcortin containing fraction of ran serum migrates faster than albumin at pH values below 7, whereas at higher pH it behaves as an alpha globulin. The alpha- acid glycoprotein (orsomucoid) has been prepared by a combination of precipitation and chromatographic procedures. The interaction of progesterone with this glycoprotein has been found to be highly dependent on temperature; the association constant decreases with increasing temperature. A strong dependency on pH has also been observed; the association constant is highest at pH 8 and decreases to about 1/20 of this value at pH 2.3. The number of binding sites for progesterone has been determined to be n = 1 at pH 7.4, 4 degrees C; the free energy of binding has the relatively high value of -7.5 kilocalories per mole. Partial removal of sialic acid from the orosomucoid preparations reduced the binding affinity for progesterone. In biological assay studies on the ligated uterus horn of the mouse it was observed that progesterone is inactivated by binding to the alphaacid blycoprotein.
715 citations
TL;DR: Preliminary data indicate that the protein is unique to sarcoplasmic reticulum and that it is hydrophobically bonded on the interior of these vesicles, and the name Calsequestrin is suggested for the protein.
Abstract: An acidic protein has been extracted from sarcoplasmic reticulum with KCl and deoxycholate. The protein, which remains soluble after extraction, has been highly purified by fractionation on DEAE-cellulose, Sephadex, and hydroxylaptite. It has a molecular weight of 44,000 and contains 392 amino acid residues per molecule, of which 146 are either glutamic or aspartic acid. No phosphorus, sialic acid, or lipid has been detected in the preparation. The protein has been shown to bind up to 970 nmol of Ca++ per mg (43 mol/mol) at pH 7.5, with an apparent dissociation constant of 4 × 10-5 M. Preliminary data indicate that the protein is unique to sarcoplasmic reticulum and that it is hydrophobically bonded on the interior of these vesicles. The protein is believed to play a role in sequestering calcium within sarcoplasmic reticulum. The name Calsequestrin is suggested for the protein.
516 citations
TL;DR: Each membrane is found to have an identifiable glycoprotein subunit pattern composed of at least 6 to 11 different sized subunits, and most of the staining intensity is present in one to three subunits.
504 citations
TL;DR: Evidence is presented to establish the identity of the radioactive derivative as 5-acetamido-3, 5-dideoxy-l-arabino-2-heptulosonic acid and to indicate it as the sole site of tritium incorporation in the carbohydrate chain.
479 citations
TL;DR: Evidence is presented to identify plasma membranes of liver as the major locus of binding for circulating glycoproteins and the binding process involves a dual role for sialic acid in that its presence on the membranes is essential, whereas its existence on the glycoprotein is incompatible with binding.
356 citations
TL;DR: A very reactive, highly radioactive reagent designed to acylate amino groups has been synthesized: this compound, the sulphone of 35 S-labelled formylmethionyl methyl phosphate, cannot pass through the red blood cell membrane.
246 citations
TL;DR: These studies establish that homogeneous γG-immunoglobulins of man may have different sequences of sugars in their oligosaccharide chains, and show that microheterogeneity of oligOSaccharides exists in homogeneous glycoproteins secreted by a single clone of cells.
232 citations
TL;DR: Acetyl determinations indicated that the C-polysaccharide contains both N- and O-acetyl groups, whereas the B- polysaccharides contains N- acetyl but not O- faceted groups, and Acid-catalyzed methanolysis in anhydrous methanolic HCl at 65° showed that theC-poly Saccharide is much more susceptible to the cleavage than the B.
169 citations
TL;DR: Both fetal and cancerous liver cells produce α‐fetoproteins which are structurally indistinguishable and probably identical, and these proteins are probably identical.
Abstract: Alpha fetoprotein (AFP) from human fetuses and hepatocellular carcinoma patients was isolated and characterized. AFP isolated from human fetuses and patients with hepatocellular cancer gave a reaction of immunological identity in immunodiffusion. The electrophoretic mobilities of these proteins in polyacrylamide gels were identical. The formation of a 140000-molecular-weight form was also similar in the fetal and carcinoma AFPs. Gel electrophoresis in the presence of sodium dodecyl sulfate gave a molecular weight of 70000 for the single polypeptide chain of both proteins. Under these conditions the mobility of the AFPs was considerably faster than that of human transferrin and just slower than that of bovine albumin. Amino acid compositions of the 2 AFPs were similar. Peptide maps of tryptic digest of reduced and alkylated AFPs were compared and each AFP showed 30 peptides. The location of each peptide seemed to be the same on the maps of the 2 proteins. Also indistinguishable were peptide maps prepared from heat-saturated protein samples. Comparison of carbohydrate analyses of the fetal and cancer AFPs also revealed close similarity in the total amount of carbohydrate (4%) and in the relative amounts of hexose (2.2 vs. 2 for fetal and cancer respectively) hexosamine (1.2 vs. 1.1) and sialic acid (.9 vs. .9 or 2 moles of sialic acid/mole of protein). Thus both fetal and cancerous liver cells produce AFP which is structurally indistinguishable and probably identical.
TL;DR: Neither the native proteins nor the γ G glycopeptide-proteins are taken up by the liver, demonstrating the specificity of the phenomenon.
TL;DR: The effects of digesting fat cells with various combinations of C. perfringens neuraminidase and trypsin on glucose oxidation and the patterns of release of sialic acid and sialyl peptides suggest that the biological effects resulting from digesting cells with these enzymes are a consequence of cleavage of similar portions of the same or closely related membrane structures.
TL;DR: Intracerebral injections of radioactive fucose into developing rats resulted in specific labelling of the brain glycoproteins in their fucoses moieties, resulting in a high degree of specificity for thelabelling of sialic acid moieties in glycoproteinins and gangliosides.
Abstract: — Intracerebral injections of radioactive fucose into developing rats resulted in specific labelling of the brain glycoproteins in their fucose moieties. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate revealed that the radioactive glycoproteins were very heterogeneous with regard to molecular weight. A procedure utilizing [3H]fucose and [14C]fucose together with double-label counting techniques was developed for comparing the electrophoretic patterns of newly synthesized glycoproteins from different samples of tissue. By the use of this procedure we showed that the incorporation of radioactive fucose into the glycoproteins of high mol. wt. was relatively greater in the brains of 5-day-old rats than in those of 25-day-old rats. Intracerebral injection of N-[Ac-3H]acetyl-d-mannosamine resulted in a high degree of specificity for the labelling of sialic acid moieties in glycoproteins and gangliosides. The ratio of the d.p.m. of N-[3H]acetylmannosamine incorporated into glycoproteins to the d.p.m. incorporated into gangliosides was higher in 5-day-old rats than in 15- or 25-day-old rats. Experiments in which 15-day-old rats were injected with a mixture of [14C]fucose and N-[3H]acetylmannosamine showed that there were differences in the relative degrees of incorporation of the two radioactive precursors into the various glycoproteins. The greatest incorporation of [14C]fucose relative to that of N-[3H]acetylmannosamine occurred in some of the glycoproteins of smaller mol. wt.
TL;DR: A close relationship exists between decreased alpha filaments, bulging pseudopodia, and loss of contact inhibition of movement in transformed cells, which is suggested to be important in cell motility.
Abstract: Two contact-inhibited "revertant" cell lines were isolated from an SV40-transformed mouse 3T3 cell line (SV-3T3) after exposure to 5-fluoro-2'-deoxyuridine. Revertant cells resembled 3T3 cells morphologically and grew to saturation densities which were similar to those of 3T3 cells; however, revertant cells readily formed both single and multinucleated giant cells in confluent cultures. SV40 virus was rescued from revertant cells by fusion with permissive monkey cells. The rescued virus transformed 3T3 cells with the same efficiency as wild type virus, and produced transformed colonies which were phenotypically similar to those produced by wild type virus. The revertant cells also resembled normal 3T3 cells in that they contained higher quantities of sialic acid than SV-3T3 cells. An inverse correlation was found between the saturation density of cells and their sialic acid content. Collagen content, however, of revertant cells was similar to that of SV-3T3 cells. The data presented suggest that the property of contact inhibition in revertant cells is related to the sialic acid content of the plasma membrane and that changes in sialic acid content of transformed cells are not directly specified by the viral genome.
TL;DR: The data suggest that a molecule containing sialic acid may be the receptor for the toxin, and the activity of gangliosides in suppressing the potency of botulinum toxin was a function of the number of sIALic acid residues in the lipid.
Abstract: A number of lipids known to be constituents of nerve-ending membranes were tested for their ability to inactivate botulinum toxin Inactivation of the toxin by a lipid was taken as presumptive evidence that the lipid might be the in vivo receptor for the toxin Several sphingolipids (sphingosine, galactosylceramide, glucosylceramide, lactosylceramide, cytolipin K and cytolipin R), steroids (cholesterol and deoxycholic acid) and fatty acids (palmitic acid, stearic acid, prostaglandin E1) did not affect the potency of botulinum toxin, and thus were discounted as potential toxin receptors However, the gangliosides did inactivate botulinum toxin rapidly (in less than 5 min), within a temperature range of 2°-40°C, and at ionic strengths of 005-040 Inactivation diminished as pH fell below 6 The activity of gangliosides in suppressing the potency of botulinum toxin was a function of the number of sialic acid residues in the lipid Thus, the data suggest that a molecule containing sialic acid may be the receptor for the toxin
TL;DR: An approximate correlation exists between the calcium uptake and the sialic acid content of erythrocytes of various species and of human ery Throcytes that have been partially depleted of sIALic acid by treatment with neuraminidase.
Abstract: 1. Washed human erythrocytes, suspended in iso-osmotic sucrose containing 2.5mm-calcium chloride, bind about 400μg-atoms of calcium/litre of packed cells. Sucrose may be replaced by other sugars. 2. Partial replacement of sucrose by iso-osmotic potassium chloride diminishes the uptake of calcium, 50% inhibition occurring at about 50mm-potassium chloride. 3. Other univalent cations behave like potassium, whereas bivalent cations are much more inhibitory. The tervalent cations, yttrium and lanthanum, however, are the most effective inhibitors of calcium uptake. 4. An approximate correlation exists between the calcium uptake and the sialic acid content of erythrocytes of various species and of human erythrocytes that have been partially depleted of sialic acid by treatment with neuraminidase. However, even after complete removal of sialic acid, human erythrocytes still bind about 140μg-atoms of calcium/litre of packed cells. 5. A Scatchard (1949) plot of calcium uptake at various Ca2+ concentrations in the suspending media shows the presence of three different binding sites on the external surface of the human erythrocyte membrane. 6. Erythrocyte `ghost' cells, the membranes of which appear to be permeable to Ca2+ ions, can bind about 1000μg-atoms of calcium per `ghost'-cell equivalent of 1 litre of packed erythrocytes. This indicates that there are also binding sites for calcium on the internal surface of the erythrocyte membrane.
TL;DR: A Golgi apparatus-rich fraction from rat liver was examined for the ability to mediate steps involved in the biosynthesis of glycoproteins, and it is suggested that the alkali-stable products might represent glycosaminoglycans, while the more alkala-labile products may be glycosamine-labiles.
TL;DR: Complete amino acid analyses of purified Clq from human serum indicate that this glycoprotein has an unusual composition for a serum protein, which includes hydroxyproline, hydroxylysine and high levels of glycine.
TL;DR: A tentative structure is proposed for the oligosaccharide moiety of glycopeptide GPIV, which has been studied by sequential hydrolysis with specific glycosidases and Pronase digestion of MN-active sialoglycopeptides derived from human erythrocytes.
Abstract: Studies have been made on the oligosaccharide residues of the alkali-stable carbohydrate–protein linkage of sialoglycopeptides derived from human erythrocytes. Four glycopeptides were isolated after alkaline borohydride treatment and Pronase digestion of MN-active sialoglycopeptides. The structure of one of these glycopeptides (GPIV) has been studied by sequential hydrolysis with specific glycosidases. Glycopeptide GPIV contained (per mol): 1mol of fucose, 1mol of sialic acid, 3mol of galactose, 3mol of mannose, 4mol of acetylglucosamine, 1mol of aspartic acid and fractional amounts of threonine, serine and glycine. The molecular weight of the glycopeptide was estimated to be 2330 by gel filtration. On the basis of glycosidase-digestion results, a tentative structure is proposed for the oligosaccharide moiety of glycopeptide GPIV.
TL;DR: Tris-soluble polypeptides obtained from totally delipidated human serum very low density lipoprotein were isolated and characterized by a newly developed method of isoelectric focusing in a narrow pH gradient and had an amino acid composition different from the major proteins of the high density or lowdensity lipoproteins.
TL;DR: Results confirm the identity of the two heterosaccharide chains of human transferrin and show that mannose was a branch point and that each sialic acid residue was linked to galactose.
TL;DR: Phosphotungstic acid used at different concentrations in water was combined with various compounds and indicated that PTA interacts with positively charged groups, that the sugar-hydroxyls do not take part in the interaction and that the type of binding involves electrostatic forces.
Abstract: In this study histochemical experiments have been carried out in order to understand the “staining mechanism” of phosphotungstic acid (PTA). One of the main objectives of this project was to investigate the mode of interaction of the heavy metal and to define the type of functional groups in the substrates responsible for PTA binding. Therefore, tissues containing known macromolecules were selected and utilized as model systems. Epiphyseal cartilage, rat sublingual glands, human bone and purified collagen were used to study the interaction of the polyacid with chondroitin sulfate (cartilage), sialic acid (sublingual gland) and collagen (purified collagen and bone). The results obtained suggested that PTA does not interact with chondroitin sulfate, with sialic acid or with the hydroxyl groups of the sugar moieties of these macromolecules. Rather, the binding appeared to be selective for positively charged groups. Since PTA interaction to organic cations was pH-dependent, it is suggested that the heavy metal binds by means of coulombic forces and that no hydrogen bonds are involved. Although phosphotungstic acid (PTA) is extensively used in electron microscopy as a “coloring agent,” comparatively few investigators have attempted to study its “staining” mechanism and to identify the type of functional groups involved in the interaction. Recently, Pease (11), in investigations on different animal tissues, suggested that this heteropolyacid “stains” acid mucopolysaccharides. Theoretical reasons were given to account for the specificity of PTA for polysaccharides and it was stated that the protein moiety of these complex macromolecules did not take part in the interaction. Based on the chemical structure of PTA, it was further suggested that the linkage of the heavy metal to hydroxyl and/or carboxyl groups in the polysaccharide chain was hydrogen bonding, and coulombic forces were not considered to play any role in PTA binding. Rambourg (14) and Marinozzi (7) supported Pease’s findings and indicated that periodic acid-Schiff (PAS)
TL;DR: Native bovine prothrombin was shown to have a circulatory half-life of 90 minutes when injected into the circulatory system of rats and therefore the possibility that sialic acid may function in determining thecirculatory life of glycoproteins is widened.
Journal Article•
TL;DR: The results indicated that MIF is a glycoprotein and that sialic acid is necessary for its biologic activity.
Abstract: Migration inhibitory factor (MIF) obtained from sensitized guinea pig lymph node lymphocytes that had been stimulated by specific antigen ( o -chlorobenzoyl-bovine γ globulin) was characterized by enzymatic treatment and isopycnic centrifugation in a CsCl density gradient. MIF incubated with water-insoluble chymotrypsin lost its biologic activity. Further, neuraminidase, which hydrolyzes terminal sialic acid, abolished MIF activity. When MIF was centrifuged in CsCl density gradients, it had a buoyant density (ρ25 = 1.430) slightly greater than that of the protein reference substance (ρ25 = 1.352), which is consistent with its being a glycoprotein. The results indicated that MIF is a glycoprotein and that sialic acid is necessary for its biologic activity.
TL;DR: The gel filtration on Sephadex G-100, disc electrophoreses, amino acid analyses, and bioassays indicated that the α and β subunits of LH represent two nonidentical and noncovalently linked components of LH.
TL;DR: It has been concluded that reliable structural information can be obtained from small amounts (less than 50 micro g) of a purified glycosphingolipid.
TL;DR: It is indicated that neuraminidase treatment of fat cells does not mimic the action of trypsin and that some commercially available preparations of neuramidase and phospholipase C from C. perfringens contain insulin-like impurities.
TL;DR: The increase in neutral sugar and the decrease in sialic acid found in cell membrane from the RBA-converted cells are chemical modifications of the cell surface which reflect conversion by an oncogenic virus and are not the result of virus infection per se.
TL;DR: The results of sialic acid assays showed that the difference between the pairs of bands was caused by differing numbers of sIALic acid residues (0–5) per molecule of protein, but that siali acid was not responsible for the differences between the bands within a pair.
Abstract: Homozygous cattle transferrin has been fractionated into six main peaks by DEAE-Sephadex chromatography. These correspond to the six transferrin components seen in starch gel electrophoresis of normal serum. In addition, six more minor components were isolated from DEAE-Sephadex, making 12 in all, and these could be divided into six pairs. Treatment of whole transferrin with neuraminidase yielded only two bands. Treatment of the individual fractionated bands showed that the slower band of each pair had the same mobility as the slow band from treated whole transferrin, while the faster band from each pair corresponded with the fast band of treated whole transferrin. These observations, and the results of sialic acid assays, showed that the difference between the pairs of bands was caused by differing numbers of sialic acid residues (0–5) per molecule of protein, but that sialic acid was not responsible for the difference between the bands within a pair. The mode of genetic control is discussed and probably involves three loci. Other physicochemical properties of cattle transferrins, namely, molecular weight, effect of iron addition, and behavior in isoelectric focusing, were also studied.