Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.99.10 (sialyltransferase)
 1,547 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Highly purified fractions of gamma-glutamyl transpeptidase [gamma-glutamyltrinsferase; (5-glutamyl)-peptide:amino-acid 5-glutamyltransferase, EC 2.3.2.2] from normal and malignant rat mammary tissue were prepared. Analyses by isoelectric focusing indicate the existence of at least 12 enzymatically active species. The gamma-glutamyl transpeptidase from the tumor tissue had a greater proportion of the activity concentrated in the more negative species than the enzyme from normal tissue. Treatment of the two enzyme preparations with neuraminidase (acylneuraminyl hydrolase, EC 3.2.1.18) greatly reduced this difference. When whole tissue homogenates were treated with papain to solubilize the enzyme and then focused, the same relationship held. The neuraminidase activities in the two homogenates were similar, but the sialytransferase activity (CMP-N-acetylneuraminate:D-galactosyl-glycoprotein N-acetylneuraminyltransferase, EC 2.4.99.1) of the tumor homogenate was 13 times that of the normal mammary homogenate. These observations suggest that the gamma-glutamyl transpeptidase of the tumor is more heavily sialylated than that from the normal tissue, possibly reflecting the greater sialyltransferase activity of the tumor.
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PMID:Differences in the isoelectric focusing patterns of gamma-glutamyl transpeptidase from normal and cancerous rat mammary tissue. 2 38

A sialyltransferase (CMP-N-acetylneuraminate:D-galactosyl-glycoprotein N-acetylneuraminyltransferase, EC 2.4.99.1) which attaches N-acetylneuraminic acid to the terminal end of the carbohydrate chain of kappa-casein was found to be concentrated in Golgi apparatus-enriched fractions of bovine mammary gland. Maximum sialyltransferase activity was obtained at pH 5.5 and 37 degrees C in the presence of 1 mM dithiothreitol and Triton X-100. A Km of 0.19 mg asialo-kappa-casein/ml (0.01 mM) was obtained for the sialyltransferase. Native kappa-casein also served as acceptor for N-acetylneuraminic acid transferase of Golgi apparatus-enriched fractions although at a slower rate than did asialo-kappa-casein. The sialyltransferase has a divalent cation requirement for maximum activity which was best satisfied by the presence of 10 mM Mn2+.
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PMID:Glycosylation of kappa-casein. I. Localization and characterization of sialyltransferase in bovine mammary gland. 3 13

Triton X-100 is increasingly effective in solubilizing human liver glycoprotein (asialofetuin) sialytransferase (CMP-N-acetylneuraminate:D-galactosyl-glycoprotien N-acetylneuraminyltransferase, EC 2.4.99.1) activity as its concentration is increased in the homogenizing buffer. At the optimal concentration of 1.5% (v/v), essentially all of the homogenate sialyltransferase activity was solubilized into the supernatant fluid. Higher concentrations of Triton X-100 inhibited sialyltransferase activity. Several kinetic properties of the solubilized asialofetuin-sialyltransferase activity were compared to those of the membrane-bound enzyme(s) (in homogenates made without Triton X-100 or in resuspended pellets). No major difference was apparent, suggesting that solubilization has not significantly altered the properties of sialyltransferase. The solubilized sialyltransferase activity is quite unstable, losing approximately 50% of its activity after one week of storage at 4 degrees C. Various detergents (Zwittergent, sodium taurocholate and sodium deoxycholate) are differentially effective in stabilizing the solubilized activity. Sodium taurocholate (1.5%, w/v) was most effective with no loss in activity after 40 days and minimal loss (14%) after 60 days storage at 4 degrees C. The solubilized sialyltransferase preparation retains full activity after storage in the frozen state (-20 degrees C) for at least 159 days.
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PMID:Solubilization and stabilization of human liver glycoprotein sialyltransferase. 3 14

Mouse cells transformed by a temperature-sensitive mutant of simian virus 40 belonging to complementation group A lost their ability to regulate cell growth when grown at the permissive temperature (35 degrees) but showed the low saturation density of cell growth at the restrictive temperature (39.5 degrees) that is characteristic of normal cells in vitro. Biochemical analysis of the membranes of cells grown under the restrictive and the permissive conditions demonstrated no qualitative temperature-dependent differences either in neutral glycolipids or in acidic glycolipids of the cells. Plasma membrane glycoproteins labeled with radioactive glucosamine showed significantly different patterns on both polyacrylamide gel electrophoresis and electrofocusing. When the levels of glycoprotein glycosyltransferases of the cells were examined, the level of sialyltransferase (CMP-N-acetylneuraminytransferase,EC 2.4.99.1) of the cells grown at the restrictive temperature was low compared with that of cells grown at the permissive temperature. Our results indicate that the level of sialyltransferase is under the control of the gene A function of simian virus 40 and consequently is related to alterations in the cell surface glycoproteins.
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PMID:Alterations in surface glycoproteins and level of sialyltransferase of cells transformed by a temperature-sensitive mutant of simian virus 40. 18 85

Sialyltransferase (EC 2.4.99.1) is released in large amounts by two hepatoma cell lines (SK-H-MA and CLH) established from patients with hepatocellular carcinoma (hepatoma). This release requires protein synthesis and glycoprotein synthesis, but not cell division. In contrast, sialyltransferase is released in minimal amounts by a cell line derived from normal human liver (Chang). The hepatoma cells also contain more surface and cellular sialyltransferase activity than Change cells. Hepatoma sialyltransferase has properties similar to other sialyltransferases. Using a calibrated Sephadex G-200 column, it is resolved into two forms with molecular weights of 65 000 and 80 000.
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PMID:The specific release of sialytransferase activity by human hepatoma cell lines. 22 27

Two different sialyltransferases (EC 2.4.99.1) have been resolved from Triton X-100 extracts of porcine submaxillary glands by affinity chromatography on CDP-hexanolamine agarose. The predominant sialyltransferase of this tissue, a CMP-N-acetylneuraminate: alpha-D-N-acetylgalactosaminide alpha2 leads to 6 sialyltransferase, has been obtained in a partially purified and stable form. A less abundant but highly active enzyme, a CMP-N-acetylneuraminate: beta-D-galactoside alpha2 leads to 3 sialyltransferase, was purified over 90,000-fold to homogeneity. Chromatography of the latter enzyme on Sephadex G-200 separated two noninterconverting forms, designated A and B, with Stokes radii of 51 A and 31 A, respectively. Both forms have equal specific activity toward lactose and contain a single polypeptide with a molecular weight of about 50,000 as estimated by gel electrophoresis. Form A appears to bind 1.18 g of Triton X-100 per g of protein, or nearly an entire detergent micelle per polypeptide, while Form B binds little or no detergent. The enzymatic properties of both forms are similar (Rearick, J.I., Sadler, J.E., Paulson, J.C., and Hill, R.L. (1979) J. Biol. Chem. 254, 4444-4451) supporting the conclusion that Form A may represent the native sialyltransferase with an intact membrane-binding site, and Form B may be a large proteolytic fragment of Form A.
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PMID:Purification to homogeneity of a beta-galactoside alpha2 leads to 3 sialyltransferase and partial purification of an alpha-N-acetylgalactosaminide alpha2 leads to 6 sialyltransferase from porcine submaxillary glands. 43 96

By means of affinity chromatography on CDP-hexanolamine-agarose, a CMP-N-acetylneuraminate: alpha-N-acetylgalactosaminide alpha 2 leads to 6 sialyltransferase (EC 2.4.99.1) has been purified 117,000-fold to homogeneity from Triton X-100 extracts of porcine submaxillary glands. The enzyme consists of several electrophoretic forms that can be partially resolved by chromatography on Sephadex G-200, the largest of which has a molecular weight of approximately 160,000 as estimated by sodium dodecyl sulfate-gel electrophoresis. Periodate oxidation studies show that the linkage formed by this enzyme with ovine submaxillary asialo-mucin as the acceptor substrate is NeuAc alpha 2 leads to 6GalNAc alpha 1 leads to O-Thr/Ser. On the basis of initial rate studies and the patterns of inhibition observed with alternate acceptor substrates, the transferase is proposed to have either a random equilibrium kinetic mechanism or an ordered steady state mechanism with the acceptor substrate binding first. Among a wide variety of oligosaccharides, glycoproteins, and simple glycosides (including p-nitrophenyl-alpha-N-acetylgalactosaminide), the only acceptor substrates for this enzyme are those glycoproteins containing the structure, R leads to 3GalNAc alpha 1 leads to O-Thr/Ser, where R may be H or a beta-galactoside.
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PMID:Purification to homogeneity and enzymatic characterization of an alpha-N-acetylgalactosaminide alpha 2 leads to 6 sialyltransferase from porcine submaxillary glands. 44 88

An inhibitory effect due to broken cells is observed when sialyltransferase (CMP-N-acetylneuraminate:D-galactosyl-glycoprotein N-acetylneuraminyltransferase, EC 2.4.99.1) is measured with mixture of intact and homogenized lymphocytes. This intracellular inhibitory factor ib purified and characterized as CMP-N-acetylneuraminic acid (CMP-NeuNAc) by its behavior in various chromatographic and electrophoretic systems and by its susceptibility to CMP-NeuNAc hydrolase. This endogenous CMP-NeuNAc leads to an isotopic dilution of the exogenous labelled CMP-NeuNAc explaining the apparently lower activity of homogenate when compared to whole cells. Consequently, the radioactivity bound to acceptors may not be related to a known number of sialyl residues transferred, calling into question the validity of comparing the incorporation of [14C]NeuNAc by homogenate and whole cells in order to assign sialyltransferase activity to ectoenzyme. A new approach is developed to detect ectoglycosyltransferases with whole cells, taking into account that both intracellular enzymes and endogenous precursor may be introduced by the small percentage of broken cells.
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PMID:Detection of ectosiallyltransferase activity using whole cells. Correction of misleading results due to the release of intracellular CMP-N-acetylneuraminic acid. 48 88

CDP-hexanolamine agarose was used as an affinity adsorbent to purify a CMP-N-acetylneuraminate: beta-D-galactosyl-glycoprotein N-acetylneuraminyltransferase (EC 2.4.99.1) from bovine colostrum. Upon binding of the enzyme to the adsorbent, elution is achieved either nonspecifically, with 0.5 to 1.0 M sodium chloride, or specifically, with CDP. A highly purified sialyltransferase is obtained with a specific activity 440,000 times that of whole colostrum. Fractionation of the purified enzyme by gel filtration gives two species with different molecular weights but equal specific activities toward asialo-alpha1-acid glycoprotein (26.0 to 28.0 micronmol/min/mg of enzyme). The molecular weights of these two forms are about 56,000 and 43,000 as judged by sodium doedcyl sulfate-gel electrophoresis, sedimentation equilibrium, and gel filtration. The catalytic properties of both forms have been examined (Paulson, J. C., Rearick, J. I., and Hill, R. L. (1977) J. Biol. Chem. 252, 2363-2371). It is concluded that the lower molecular weight form may be a partially degraded species of the enzyme of higher molecular weight.
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PMID:Purification of a sialyltransferase from bovine colostrum by affinity chromatography on CDP-agarose. 84 32

Levels of glycoprotein:sialyltransferase activity (EC 2.4.99.1; CMP-acetyl-neuraminate:D-galactosyl-glycoprotein N-acetylneuraminyl-transferase) were measured in plasma of patients with neoplastic disease, and were found elevated above normal control values in 85% of patients examined. There was a correlation between enzyme levels and course of disea-e in 46 of 57 patients studied serially during therapy. Plasma sialyltransferase may be a useful marker enzyme for monitoring effectiveness of therapeutic programs for disseminated neoplasms.
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PMID:Alterations in plasma sialyltransferase levels in patients with neoplastic disease. 91 50


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