To gain insight into the binding manner of androst-4-ene-6, 17-dione (4) and its 5-en-4-one analog 9, good competitive inhibitors of aromatase, in the active site of the enzyme, their 19-oxygenated derivatives were evaluated as inhibitors of human placental aromatase. The 19-hydroxy steroids 6, 7, and 10 and the 19-oxo analogs 8 and 12 were much poorer competitive inhibitors than their corresponding parent 19-methyl steroids. Conversion of the 17-keto inhibitors, 4, 6, and 10 to the 17β-ols 5, 7, and 11, respectively, markedly decreased their affinity to the enzyme. The results suggest that steroids 4 and 9 would bind to the active site in a similar manner to that involved in the binding of the substrate androstenedione (1).
雄甾-4-烯-6,17-二酮(4)及其 5-烯-4-
酮类似物 9 是芳香化酶的良好竞争性
抑制剂,为了深入了解它们在该酶活性位点的结合方式,我们对其 19-氧代衍
生物作为人胎盘芳香化酶
抑制剂进行了评估。与相应的母体 19-甲基类
固醇相比,19-羟基类
固醇 6、7 和 10 以及 19-氧代类似物 8 和 12 的竞争性抑制效果要差得多。17-酮
抑制剂 4、6 和 10 分别转化为 17β-醇 5、7 和 11 后,对酶的亲和力明显下降。结果表明,类
固醇 4 和 9 与活性位点的结合方式与底物
雄烯二酮的结合方式类似 (1)。