Analysis of Heterotropic Cooperativity in Cytochrome P450 3A4 Using α-Naphthoflavone and Testosterone
Analysis of Heterotropic Cooperativity in Cytochrome P450 3A4 Using α-Naphthoflavone and Testosterone
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DOI：
10.1074/jbc.m110.182055
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发表时间：
2011-02-18
影响因子：
4.8
通讯作者：
Sligar, Stephen G.
中科院分区：
文献类型：
--
作者：
Frank, Daniel J.;Denisov, Ilia G.;Sligar, Stephen G.
细胞色素P450 3A 4（CYP 3A 4）对它代谢的许多底物（包括睾酮（TST）和α-萘酚酮（ANF））显示非米氏动力学。这两种底物之间的异嗜性效应可以进一步使酶的代谢谱复杂化。在这项工作中，已研究了纳米盘中溶解的单体CYP 3A 4与不同摩尔比的ANF和TST相互作用的能力。比较所观察到的血红素自旋状态，NADPH的消耗，和产品的形成率与非合作模型计算的线性组合的全球分析的每个基板揭示了一个详细的景观的异向性相互作用，并表明可以忽略不计的绑定之间的协同ANF和TST。观察到的ANF对TST代谢动力学的影响是由于第二底物的加和作用，没有特异性变构效应。
Cytochrome P450 3A4 (CYP3A4) displays non-Michaelis-Menten kinetics for many of the substrates it metabolizes, including testosterone (TST) and alpha-naphthoflavone (ANF). Heterotropic effects between these two substrates can further complicate the metabolic profile of the enzyme. In this work, monomeric CYP3A4 solubilized in Nanodiscs has been studied for its ability to interact with varying molar ratios of ANF and TST. Comparison of the observed heme spin state, NADPH consumption, and product formation rates with a non-cooperative model calculated from a linear combination of the global analysis of each substrate reveals a detailed landscape of the heterotropic interactions and indicates negligible binding cooperativity between ANF and TST. The observed effect of ANF on the kinetics of TST metabolism is due to the additive action of the second substrate with no specific allosteric effects.