文档介绍：华中科技大学
硕士学位论文
硒对蛋白质酪氨酸硝化及磷酸化修饰的影响
姓名:杨琳
申请学位级别:硕士
专业:无机化学
指导教师:黄开勋
2011-01-08
华中科技大学硕士学位论文
摘要
在氧化应激状态下,活性氮分子(RNS)能够诱导慢性炎症和胰岛素抵抗。RNS中
的过氧亚硝酸根离子(ONOO¯)能够引起蛋白质酪氨酸残基的硝化,而酪氨酸的硝化对
磷酸化信号传导的影响很可能是RNS诱发胰岛素抵抗的机制之一。硒(selenium)是哺
乳动物必需的微量营养元素,以硒代半胱氨酸(selenocysteine)的形式存在于机体的
各种硒蛋白中,且为硒蛋白的活性中心或必需组成成份。近年来的研究发现,硒除
了具有抗氧化、增强机体的免疫功能外,还具有类胰岛素的作用,然而硒与糖尿病
的关系,硒对蛋白质的硝化和磷酸化信号有怎样的影响亦不清楚。
本文采用免疫印迹的方法,通过对体外HepG2细胞及小鼠体内给予一定浓度的亚硒
酸钠后,研究补硒对蛋白质硝化及磷酸化的影响。主要结果如下:
(1)在 HepG2细胞实验中,在培养液中加入0~300 nM的 Na2SeO3 溶液后,HepG2
细胞的存活率没有显著性差别,而且硒能够抑制ONOO¯诱导的蛋白质硝化,但对磷
酸化作用的规律则不明显。
(2)在糖尿病模型小鼠实验中,硒能降低糖尿病小鼠血糖,补硒组组织中蛋白
质的硝化弱于正常组及糖尿病组,磷酸化水平虽然受到一定的影响,但依然没有明
显规律。
补硒对蛋白质硝化作用的抑制可能与硒蛋白对ONOO¯的清除作用有关,然而补
硒对蛋白质磷酸化的影响的机理有待进一步研究。
关键词:硒;氧化应激;硝化;磷酸化;胰岛素信号转导;免疫印迹
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华中科技大学硕士学位论文
Abstract
Reactive nitrogen species (RNS) can induce the chronic inflammation and insulin
resistance while the Peroxinitrite ions (ONOO¯), one of RNS, may result in the nitration and
affect phosphorylation of tyrosine in proteins, which may be one of the mechanisms.
Selenium, as an essential nutritional trace element for mammals,exerts its biological
effect through selenoproteins which incorporate selenium in the form of one or more
selenocysteine residues. Recently, it is suggested that selenium has an insulin-mimetic action
in addition to antioxidation and improving immune function, however, the relationship among
selenium, the diabetes, proteins nitration and phosphorylation remains elusive.
In this paper, hepatoma HepG2 cells and diabetes rats were given ectogenous sodium
selenite solution to investigate the changes of protein nitration and phosphorylation. The
results are as follows:
(1) In the HepG2 cells, after the supplement of 0 to 300 nM sodium selenite solutions,
there was no significant difference in the cells viability, however, the supplementation of
selenium could reduce the proteins, nitrition induced by ONOO¯, compared with control
cells, however, there were n