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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
1996-3-1
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pubmed:abstractText |
Polysialic acid (PSA) is a linear homopolymer of alpha-2,8-linked sialic acid residues whose expression is developmentally regulated and modulates the adhesive property of the neural adhesion molecule, N-CAM. Recently, hamster and human cDNAs encoding polysialyltransferase (PST-1 for the hamster enzyme and PST for the human enzyme) were cloned, and by using the human cDNA it was demonstrated that the expression of PSA in N-CAM facilitates neurite outgrowth (Nakayama, J., Fukuda, M.N., Fredette, B., Ranscht, B., and Fukuda, M. (1995) Proc. Natl. Acad. Sci. U.S.A., 92, 7031-7035; Eckhardt, M.A., Mühlenhoff, M., Bethe, A., Koopman, J., Frosch, M., and Gerardy-Schahn, R. (1995) Nature 373, 715-718.) Although these studies demonstrated that PST-1 and PST synthesize PSA in cultured cells, it was not shown that they could catalyze the polycondensation of alpha-2,8-linked sialic acid on a glycoconjugate template containing alpha-2,3-linked sialic acid. Here we demonstrate that PSA formation by PST is independent from the presence of N-CAM in vivo. We then develop an in vitro assay of PSA synthesis using glycoproteins other than N-CAM as acceptors and a soluble PST as an enzyme source. The soluble PST, produced as a chimeric protein fused with protein A, was incubated with rat alpha 1-acid glycoprotein, fetuin or human alpha 1-acid glycoprotein as acceptors together with the donor substrate CMP-[14C]NeuNAc. Incubation of fetuin with the soluble PST, in particular, resulted in a high molecular weight product that was susceptible to PSA-specific endoneuraminidase. Polysialylated products were not formed when alpha-2,3-linked sialic acid was removed from the acceptor fetuin before incubation. These results establish that a single enzyme, PST, alone can catalyze both the addition of the first alpha-2,8-linked sialic acid to alpha-2,3-linked sialic acid and the polycondensation of all alpha-2,8-linked sialic acids, yielding PSA.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/CMP-N-acetylneuraminate-poly-alpha-2...,
http://linkedlifedata.com/resource/pubmed/chemical/DNA Primers,
http://linkedlifedata.com/resource/pubmed/chemical/Neural Cell Adhesion Molecules,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Fusion Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Sialic Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Sialoglycoproteins,
http://linkedlifedata.com/resource/pubmed/chemical/Sialyltransferases,
http://linkedlifedata.com/resource/pubmed/chemical/alpha-Fetoproteins,
http://linkedlifedata.com/resource/pubmed/chemical/polysialic acid
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
26
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pubmed:volume |
271
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1829-32
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:8567623-Animals,
pubmed-meshheading:8567623-Base Sequence,
pubmed-meshheading:8567623-Carbohydrate Sequence,
pubmed-meshheading:8567623-Cell Line,
pubmed-meshheading:8567623-Cercopithecus aethiops,
pubmed-meshheading:8567623-DNA Primers,
pubmed-meshheading:8567623-Humans,
pubmed-meshheading:8567623-Molecular Sequence Data,
pubmed-meshheading:8567623-Neural Cell Adhesion Molecules,
pubmed-meshheading:8567623-Recombinant Fusion Proteins,
pubmed-meshheading:8567623-Recombinant Proteins,
pubmed-meshheading:8567623-Sialic Acids,
pubmed-meshheading:8567623-Sialoglycoproteins,
pubmed-meshheading:8567623-Sialyltransferases,
pubmed-meshheading:8567623-Substrate Specificity,
pubmed-meshheading:8567623-alpha-Fetoproteins
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pubmed:year |
1996
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pubmed:articleTitle |
A human polysialyltransferase directs in vitro synthesis of polysialic acid.
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pubmed:affiliation |
Glycobiology Program, La Jolla Cancer Research Foundation, California 92037, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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