Institute of Biomedical Chemistry, Pogodinskaya Street, 10, Build 8, Moscow 119121, Russia; Pirogov Russian National Research Medical University, Ostrovitianov Street, 1, Moscow 117997, Russia.
Institute of Biomedical Chemistry, Pogodinskaya Street, 10, Build 8, Moscow 119121, Russia.
J Inorg Biochem. 2018 Sep;186:24-33. doi: 10.1016/j.jinorgbio.2018.05.010. Epub 2018 May 21.
Abiraterone and galeterone induce type I differential spectral changes in human sterol 14α-demethylase (cytochrome P450 51A1, CYP51A1) with the sigmoidal shape of the binding curve. After approximation of the data by Hill model, the half-saturation concentrations (K) were estimated as 22 ± 1 μM and 16 ± 1 μM and the Hill coefficients as 2.4 ± 0.2 and 1.97 ± 0.23 for abiraterone and galeterone, respectively. We analyzed the catalytic activity of CYP51A1 towards abiraterone and galeterone using an electrochemical system based on recombinant CYP51A1 immobilized on the screen-printed graphite electrode (SPE) modified by didodecyldimethylammonium bromide (DDAB) film. The study revealed the amperometric response of CYP51A1 upon addition of abiraterone, which may indicate the substrate properties of abiraterone towards CYP51A1. Galeterone caused negligible amperometric response of CYP51A1. Mass-spectrometric analysis of the products of CYP51A1-dependent electrocatalytic reaction at a controlled potential towards abiraterone and galeterone revealed products with m/z of 366.3 and 405.2, respectively, indicating monohydroxylation of abiraterone and galeterone. We have observed the sigmoidal character of the dependence of the catalytic current on abiraterone concentration. Analysis of molecular docking data demonstrated the ability of abiraterone and galeterone to bind to the active site of CYP51A1, but abiraterone occupies the position closer to the heme.
阿比特龙和加特勒酮诱导人固醇 14α-去甲基酶（细胞色素 P450 51A1，CYP51A1）发生 I 型差谱变化，其结合曲线呈 S 形。通过 Hill 模型对数据进行近似后，分别估算出阿比特龙和加特勒酮的半饱和浓度（K）为 22±1μM 和 16±1μM，Hill 系数为 2.4±0.2 和 1.97±0.23。我们使用基于固定在通过二癸基二甲基溴化铵（DDAB）修饰的丝网印刷石墨电极（SPE）上的重组 CYP51A1 的电化学系统分析 CYP51A1 对阿比特龙和加特勒酮的催化活性。该研究揭示了 CYP51A1 加入阿比特龙后的安培响应，这可能表明阿比特龙是 CYP51A1 的底物。加特勒酮对 CYP51A1 的安培响应可忽略不计。在控制电位下对 CYP51A1 依赖的电催化反应产物进行质谱分析，得到的产物的质荷比分别为 366.3 和 405.2，表明阿比特龙和加特勒酮发生了单羟基化。我们观察到催化电流对阿比特龙浓度的依赖性呈 S 形。分子对接数据分析表明，阿比特龙和加特勒酮能够与 CYP51A1 的活性位点结合，但阿比特龙占据更接近血红素的位置。
