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

通过1997年和19981两年的项目，我们取得了以下成果。用GC-MS分析了自杀底物Delta^lt；1_&gt；、Delta^&lt；6_&gt；和Delta^&lt；1.6_gt；雄烯二酮(AD)及其6-烷基类似物与人胎盘芳香酶的芳构化反应动力学。在每个系列中，6-烷基的立体化学和长度对芳构化的影响程度不同。抑制剂的K_i和K_m值之间没有直接的相关性，但Delta^lt；1_gt；和Delta^lt；1.6_gt；AD类似物的芳构化与它们的失活反应有很好的相关性。化学合成的[19^&lt；_3&gt；H，4-^&lt；_14&gt；C]-Delta^&lt；1_&gt；-AD在释放^3HCOOH和^3HCOOH的同时发生芳构化反应，表明Delta^1-AD的芳构化机理与AD芳构化反应相同。作为芳香酶抑制剂失活剂的6-苯基脂肪族AD及其类似物Delta^lt；1_gt；、Delta^；&lt；6_&gt；和Delta^&lt；1.6_&gt；的构效关系显示了抑制剂与活性部位结合方式的新方面。A，B环体系中具有双键的三个AD的区域异构体和3-脱氧类固醇在C-19位用芳香酶氧化。5.19-氧合的4β，5β-环氧AD用芳香酶芳构化为雌酮。

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.