Domain structure of bi-functional selenoprotein P
Domain structure of bi-functional selenoprotein P
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DOI：
10.1042/bj20040328
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发表时间：
2004-08-01
影响因子：
4.1
通讯作者：
Takahashi, K
中科院分区：
文献类型：
--
作者：
Saito, Y;Sato, N;Takahashi, K
人硒蛋白P（SeP）是一种富含硒的血浆糖蛋白，推测含有10个硒代半胱氨酸残基，其中1个位于N端第40位，其余9个位于C端第3位。我们已经表明，SeP不仅催化谷胱甘肽还原磷脂酰胆碱氢过氧化物[Saito，Hayashi，Tanaka，Watanabe，Suzuki，Saito和Takahashi（1999）J.Biol.Chem.274，2866-2871]，而且还将其硒供应给增殖细胞[Saito和Takahashi（2002）Eur. 269，5746-5751]。用血浆激肽释放酶处理SeP导致连续的有限蛋白水解（Arg-235-Gln-236和Arg-242-Asp-243）。N端（残基1-235）和C端（残基243-361）片段分别具有酶活性和供硒活性。这些结果证实了SeP是一种双功能蛋白，并表明第一个硒代半胱氨酸残基是酶的活性位点，其余9个残基作为硒供应者发挥作用。
Human selenoprotein P (SeP), a selenium-rich plasma glycoprotein, is presumed to contain ten selenocysteine residues; one of which is located at the 40th residue in the N-terminal region and the remaining nine localized in the C-terminal third part. We have shown that SeP not only catalyses the reduction of phosphatidylcholine hydroperoxide by glutathione [Saito, Hayashi, Tanaka, Watanabe, Suzuki, Saito and Takahashi (1999) J. Biol. Chem. 274, 2866-2871], but also supplies its selenium to proliferating cells [Saito and Takahashi (2002) Eur. J. Biochem. 269, 5746-5751]. Treatment of SeP with plasma kallikrein resulted in a sequential limited proteolysis (Arg-235-Gln-236 and Arg-242-Asp-243). The N-terminal (residues 1-235) and C-terminal (residues 243-361) fragments exhibited enzyme activity and selenium-supply activity respectively. These results confirm that SeP is a bifunctional protein and suggest that the first selenocysteine residue is the active site of the enzyme and the remaining nine residues function as a selenium supplier.