| Project/Area Number |
10044048
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
TANIGUCHI Kazuya Hokkaido Univ., Grad. Sch. of Sci., Prof., 大学院・理学研究科, 教授 (40028204)
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| Co-Investigator(Kenkyū-buntansha) |
IMAGAWA Toshiaki Hokkaido Univ. Grad. Sch. of Sci. Asso.Prof., 大学院・理学研究科, 助教授 (20142177)
KAYA Shunji Hokkaido Univ., Grad. Sch. of Sci., Asso.Prof., 大学院・理学研究科, 助教授 (90186023)
SVEN Mardh リンシェピング大学, 生命科学部, 教授
JEFFREY Froe 米国国立衛生研究所, 老年学研究センター・兼メリーランド大学・部長, 教授
WILHELM Scho ユスタスリービッヒ大学, 生化学・内分泌学, 教授
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 2000: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1999: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1998: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Na / K-ATPase / oligomer / P-Type ATPase / Post Albers Scheme / tetraprotomer / H / リン酸化 / フォスファターゼ / 構造変化 / Naポンプ / Hポンプ |
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| Research Abstract |
Since the discovery of Na/K-ATPase, evidence has accumulated to suggest that 1 mol of ATP hydrolysis occurs via the Na^+-occluded ADP-sensitive phosphoenzyme, the K^+- sensitive phoshphoenzyme and the K^+-occluded enzyme accompanying active transport of 3Na^+ and 2K^+ according the Post-Albers sheme. However, some controversial issues have arisen concerning whether the functional unit of the enzyme is an αβ-protomer or a much higher oligomer, which would be related to the mechanism of transport, either sequential or simultaneous. Detailed studies of oligomer interaction and the reactivity of the enzyme and a comparison of the extent of phosphorylation with ligand-binding capacities in the presence or absence of ATP hydrolysis and others strongly suggest that the functional unit of the enzyme in the membrane is a tetraprotomer, (αβ)_4. They also suggest that each reaction intermediate of the Post-Albers scheme, respectively, reflects half of the site property of the intermediate and that another half binds ATP.These data may be useful not only to answer the long-standing question of whether the mechanism functions in the presence of both Na^+ and K^+ but also contribute to a better understanding of the mechanism of P-type pump ATPase in general.
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