| Project/Area Number |
12470497
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biological pharmacy
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KAWASAKI Toshisuke Grad. Sch. Pharm. Sci., Kyoto U., Professor, 薬学研究科, 教授 (50025706)
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| Co-Investigator(Kenkyū-buntansha) |
OKA Shogo Grad. Sch. Pharm. Sci., Kyoto U., Associate Professor, 薬学研究科, 助教授 (60233300)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥16,100,000 (Direct Cost: ¥16,100,000)
Fiscal Year 2001: ¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 2000: ¥9,900,000 (Direct Cost: ¥9,900,000)
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| Keywords | HNK-1 epitope / glucuronyltransferase / GlcAT-P / GlcAT-S / N-acetyllactosamine / complex type sugar chain / 細胞接着分子 / 遺伝子欠損マウス / 細胞凝集 / 免疫組織染色 / HNK-1抗原 / mRNA / 染色体遺伝子 |
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| Research Abstract |
In our previous studies, we succeeded in cloning of two kind of glucuronyltransferase (GlcAT-P and GlcAT-S) cDNAs that are responsible for the biosynthesis of the HNK-1 epitope and studied the functions of the HNK-1 epitope using these cDNAs as molecular probes. In this study, we have cloned the human GlcAT-P gene for the first time and revealed that the en-zyme is a type II membrane protein consisting of 334 amino acids and the amino acid se-quence of the catalytic region is 98.2% identical to that of rat GlcAT-P but is different from the latter in the 13 amino acid shorter C-terminal cytoplasmic domain. The human GlcAT-P gene was mapped to 11q25, which is syntenic with the mouse GlcAT-P locus, the A4 region of chromosome 9. The acceptor specificity of a rat brain glucuronyltransferase, GlcAT-P,was investigated using asialoorosomucoid as a model acceptor substrate. The enzyme trans-ferred glucuronic acid to bi-, tri-, and tetra-antennary complex type sugar chains, with almost equal efficiency, indicating that the enzyme has no preference as to the number of acceptor sugar branches. The GlcAT-P is highly specific for the terminal W-acetyllactosamine structure and no glucuronic acid was incorporated into a Galbl-3GlcNAc branch. The GlcAT-P transferred glucuronic acid to the galactose residues in each N-acetyllactosamine residue of the tetra-antennary oligosaccharide chains with different efficiencies and most preferentially to those in the Galbl-4GlcNAcbl-4Manal-3 branch. With regards to the membrane phospholipid requirement of GlcAT-P, we demonstrated that phosphatidyl inositol is required for the GlcAT-P activity to glycolipid substrate, paragloboside.
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