Zhao Jing, He Xiaolin, Yang Nana, Sun Lizhou, Li Genxi
Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, China.
Department of Obstetrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210036, China.
Int J Mol Sci. 2012;13(4):4873-4879. doi: 10.3390/ijms13044873. Epub 2012 Apr 18.
In this work, we report the studies of drug metabolism by xanthine oxidase (XOD) with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at -413.1 mV (vs. SCE) after embedding XOD in salmon sperm DNA membrane on the surface of pyrolytic graphite electrode. Then, a new steady peak can be observed at -730 mV (vs. SCE) upon the addition of 6-mercaptopurine (6-MP) to the electrochemical system, indicating the metabolism of 6-MP by XOD. Furthermore, the chronoamperometric response shows that the current of the catalytic peak located at -730 mV increases with addition of 6-MP in a concentration-dependent manner, and the increase of the chronoamperometric current can be inhibited by an XOD inhibitor, quercetin. Therefore, our results prove that XOD/DNA modified electrode can be efficiently used to study the metabolism of 6-MP, which may provide a convenient approach for in vitro studies on enzyme-catalyzed drug metabolism.
在本研究中，我们用电化学技术报道了黄嘌呤氧化酶（XOD）对药物代谢的研究。首先，将XOD包埋于热解石墨电极表面的鲑鱼精DNA膜中后，得到一对稳定、清晰且准可逆的氧化/还原峰，其形式电位为-413.1 mV（相对于饱和甘汞电极）。然后，向电化学体系中加入6-巯基嘌呤（6-MP）后，在-730 mV（相对于饱和甘汞电极）处可观察到一个新的稳定峰，表明XOD对6-MP有代谢作用。此外，计时电流响应表明，位于-730 mV处的催化峰电流随6-MP的加入呈浓度依赖性增加，且XOD抑制剂槲皮素可抑制计时电流的增加。因此，我们的结果证明，XOD/DNA修饰电极可有效地用于研究6-MP的代谢，这可能为酶催化药物代谢的体外研究提供一种便捷的方法。
