Heteromeric complex formation between CYP2E1 and CYP1A2: evidence for the involvement of electrostatic interactions.
Heteromeric complex formation between CYP2E1 and CYP1A2: evidence for the involvement of electrostatic interactions.
复制标题
CYP2E1 和 CYP1A2 之间异聚复合物的形成：静电相互作用参与的证据。
DOI：
10.1021/bi061803n
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发表时间：
2006
期刊：
影响因子：
2.9
通讯作者：
Backes,WayneL
中科院分区：
文献类型：
--
作者：
Kelley,RustyW;Cheng,Dongmei;Backes,WayneL
与包含还原酶和单一 P450 酶的简单重构系统相比，包含 CYP2B4、CYP1A2 和 NADPH-细胞色素 P450 还原酶的混合重构系统先前已显示出对 7-戊氧基试卤灵 O-脱烷基化 (PROD) 的显着抑制作用，结果与 CYP1A2-CYP2B4 复合物的形成一致，其中还原酶以高亲和力与复合物的 CYP1A2 部分。在本报告中，我们提供了 CYP1A2 和 CYP2E1 之间相互作用的证据。当这些 P450 在亚饱和还原酶浓度的混合重构系统中组合时，观察到 7-乙氧基试卤灵 O-脱乙基化 (EROD) 和 PROD 的协同作用。较高的离子强度减弱了混合重构系统中 PROD 和 EROD 的协同刺激，这与异聚 CYP2E1−CYP1A2 复合物的破坏一致。进一步检查离子强度的影响作为还原酶浓度的函数。在较低离子强度下，EROD 具有显着的协同刺激作用。这种协同刺激随着还原酶浓度的增加而减弱，当还原酶变得饱和时导致附加反应。有趣的是，在高离子强度下，混合重构系统中没有观察到 EROD 的协同作用。相反，含有 CYP2E1 和 CYP2B4 的混合重构系统没有提供这些异聚 P450−P450 复合物形成的证据。使用还原酶-CYP1A2-CYP2E1 混合重构系统观察到的协同刺激与 CYP1A2-CYP2E1 复合物的形成一致。考虑到 CYP2B4 和 CYP2E1 之间缺乏动力学可检测的相互作用，以及之前报道的 CYP1A2−CYP2B4 相互作用，这些结果表明 CYP1A2 可能促进与其他 P450 酶形成复合物。
Mixed reconstituted systems containing CYP2B4, CYP1A2, and NADPH−cytochrome P450 reductase were previously shown to exhibit a dramatic inhibition of 7-pentoxyresorufin O-dealkylation (PROD) when compared to simple reconstituted systems containing reductase and a single P450 enzyme, results consistent with the formation of CYP1A2−CYP2B4 complexes where the reductase binds with high affinity to the CYP1A2 moiety of the complex. In this report, we provide evidence for an interaction between CYP1A2 and CYP2E1. Synergism of 7-ethoxyresorufin O-deethylation (EROD) and PROD was observed when these P450s were combined in mixed reconstituted systems at subsaturating reductase concentrations. Higher ionic strength attenuated the synergistic stimulation of both PROD and EROD in mixed reconstituted systems, consistent with disruption of heteromeric CYP2E1−CYP1A2 complexes. The effect of ionic strength was further examined as a function of reductase concentration. At lower ionic strength, there was a significant synergistic stimulation of EROD. This synergistic stimulation diminished with increasing reductase concentration, resulting in an additive response as reductase became saturating. Interestingly, at high ionic strength, the synergism of EROD in the mixed reconstituted system was not observed. In contrast, mixed reconstituted systems containing CYP2E1 and CYP2B4 did not provide evidence for the formation of these heteromeric P450−P450 complexes. The synergistic stimulation observed with the reductase−CYP1A2−CYP2E1 mixed reconstituted system is consistent with the formation of a CYP1A2−CYP2E1 complex. Taken together with the lack of a kinetically detectable interaction between CYP2B4 and CYP2E1, and the previously reported CYP1A2−CYP2B4 interaction, these results suggest that CYP1A2 may facilitate the formation of complexes with other P450 enzymes.