Aromatase Reaction of Suicide Substrates of Aromatase and Their Inactivation Mechanisms.

我们通过1997年和1998年实施的项目取得了以下成果1。用GC-MS分析了芳香化酶的自杀底物DELTA^-AD<1_>、DELTA^-AD<6_>和DELTA <1.6_>^-AD及其6-烷基类似物与人胎盘芳香化酶的芳构化反应动力学，DELTA^<1_>-AD是该酶的良好底物，其芳构化反应速率与AD相当，DELTA^-AD<6_>和DELTA^<1.6_>-AD's是较差的底物。6-烷基的立体化学和长度对芳构化反应有不同程度的影响。抑制剂的K_i和K_m值之间没有直接的相关性，但DELTA_i<1_>和DELTA_i <1.6_>AD类似物的芳构化与其失活反应有很好的相关性. [19化学合成的Δ <_3>H，4-<_14>C]-Δ ^<1_>-AD发生芳构化反应，并伴随着^3H_20和^3HCOOH的释放，表明Δ ^-AD的芳构化反应与AD的芳构化反应机理相同。6-苯基脂肪族AD及其类似物<1_><6_><1.6_>作为芳香酶抑制剂失活剂的构效关系显示了抑制剂与活性位点结合方式的新方面。用芳香化酶将AD的三个A、B环上有双键的区域异构体以及3-脱氧甾体在C-19位氧化。5.19-氧化的4 β，5 β-环氧AD用芳香化酶芳构化为雌酮。

We have obtained the following results by the project carried out at 1997 and 19981. Kinetics of aromatization of suicide substrates of aromatase, DELTA^<1_>, DELTA^<6_> and DELTA^<1.6_> androstenediones (AD) and their 6-alkyl analogs, with human placental aromatase was analyzed by GC-MS.DELTA^<1_>-AD was a good substrate for the enzyme and its aromatization rate was comparable with that of AD, in contrast, DELTA^<6_> and DELTA^<1.6_>-AD's were the poor substrates. The stereochemistry and length of the 6-alkyl group affected the aromatization to a different extent in each series. There was no direct correlation etween the K_i and K_m values for the inhibitors but the aromatization of DELTA^<1_> and DELTA^<1.6_> AD analogs correlated well to their inactivation reactions.2. [19^<_3>H, 4-^<_14>C]-DELTA^<1_>-AD synthesized chemically, was aromatized accompanying with the release of ^3H_20 and ^3HCOOH, indicating that DELTA^1-AD aromatizes via the same mechanism involved in the AD aromatization.3. Structure-activity relationships of 6-phenylaliphatic AD's as well as their DELTA^<1_>, DELTA^<6_>, and DELTA^<1.6_> analogs as aromatase inhibitors inactivators showed new aspects for a binding manner of the inhibitors to the active site.4. Three regioisomers of AD having a double-bond in A, B-ring system as well as 3-deoxy steroids was oxygenated at C-19 position with aromatase.5.19-Oxygenated 4beta, 5beta-epoxy AD's were aromatized to estrone with aromatiase.