硒蛋白P的研究进展

硒蛋白P(SeP)是从大鼠和人血浆中分离、纯化得到的一种糖蛋白 ,每个硒蛋白P多肽含有10个硒代半胱氨酸。硒蛋白P中的硒含量占大鼠和人血浆中硒含量的 5 0 %以上。在其mRNA开放阅读框架中克隆的cDNA的序列含有 10个UGA密码子。硒代半胱氨酸在一个UGA密码子处嵌入蛋白的一级结构 ,尽管对硒蛋白P功能还没有彻底了解 ,它的一种非常可能的作用是作为一种胞外抗氧化剂。大鼠血浆中的硒蛋白P在体内实验中对Diquat诱导的脂质过氧化和肝损坏具有保护作用 ,人血浆中的硒蛋白P在体外实验中显示减少内毒素过氧化硝酸盐和磷脂氢过氧化物的活性。牛血浆中的硒蛋白P在神经细胞的培养中作为一存活促进因子。

The Progress on Studies of Selenoprotein P(SeP)

Selenoprotein P(SeP) is a glycoprotein that has been purified from rat and human plasma. SeP contains 10 selenocysteine residues per polypeptide. It accounts for more than 50% the selenium content in rat and human plasma. The sequence of the cloned cDNA contains 10 UGA codon in the open reading frame of mRNA Selenocysteine is incorporrated into the primary structure of the protein at a UGA codon . Although its function is still not completely understood, a function as an extracellular antioxidant seems most probable. A protective function of SeP in rat plasma against diquat-induced lipid peroxidation, liver necrosis invivo and in human plasma against the potent endotoxin peroxynitrite and phospholipid hydroperoxide reducing activity was demonstrated in vitro. SeP of bovine serum acts as a survival-promoting factor in neuronal cell culture. ;