二价金属离子对跳鲻肝脏微粒体7-乙氧基异吩恶唑酮-O-脱乙基酶（EROD）活性的抑制作用。
Inhibitory effects of divalent metal ions on liver microsomal 7-ethoxyresorufin O-deethylase (EROD) activity of leaping mullet.
作者信息
Bozcaarmutlu Azra, Arinç Emel
机构信息
Department of Biological Sciences, Joint Graduate Program in Biochemistry, Middle East Technical University, 06531 Ankara, Turkey.
出版信息
Mar Environ Res. 2004 Aug-Dec;58(2-5):521-4. doi: 10.1016/j.marenvres.2004.03.040.
The purpose of the present study was to elucidate in vitro effects of Hg(2+), Zn(2+), Ni(2+) and Cd(2+) on cytochrome P4501A1 (CYP1A1) dependent EROD activities in leaping mullet liver microsomes. Fish captured from the most polluted part of Izmir Bay, had highly elevated EROD activities, and induced CYP1A1 protein levels as determined by Western blotting. Although all of the metal ions caused inhibition of the initial velocity of the reaction, Hg(2+) and Cd(2+) exhibited much higher inhibitory effect at lower concentrations and they were evidently more potent inhibitors than others. The inhibitor concentration giving 50% inhibition (IC(50) values) of Zn(2+), Ni(2+), Cd(2+) and Hg(2+) of initial EROD activity were 107, 16, 1.3 and 0.15 micromolar, respectively. Glutathione (GSH) at 0.5 mM final concentration, completely reversed Ni(2+) and Cd(2+) inhibition of EROD activity indicating the protective action of GSH.
本研究的目的是阐明汞离子（Hg(2+)）、锌离子（Zn(2+)）、镍离子（Ni(2+)）和镉离子（Cd(2+)）对跳鲻鱼肝微粒体中细胞色素P4501A1（CYP1A1）依赖的乙氧基异吩恶唑酮-O-脱乙基酶（EROD）活性的体外影响。从伊兹密尔湾污染最严重区域捕获的鱼类，其EROD活性显著升高，且通过蛋白质免疫印迹法测定发现其CYP1A1蛋白水平也被诱导。尽管所有金属离子均导致反应初速度受到抑制，但Hg(2+)和Cd(2+)在较低浓度时表现出更高的抑制作用，且明显比其他离子更具抑制效力。使EROD初始活性产生50%抑制作用的抑制剂浓度（IC(50)值），锌离子（Zn(2+)）、镍离子（Ni(2+)）、镉离子（Cd(2+)）和汞离子（Hg(2+)）分别为107、16、1.3和0.15微摩尔。终浓度为0.5 mM的谷胱甘肽（GSH）可完全逆转镍离子（Ni(2+)）和镉离子（Cd(2+)）对EROD活性的抑制，表明GSH具有保护作用。
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