Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Chem Asian J. 2012 Oct;7(10):2286-93. doi: 10.1002/asia.201200250. Epub 2012 Jun 14.
The stereoselective epoxidation of styrene was catalyzed by H(2) O(2) -dependent cytochrome P450(SPα) in the presence of carboxylic acids as decoy molecules. The stereoselectivity of styrene oxide could be altered by the nature of the decoy molecules. In particular, the chirality at the α-positions of the decoy molecules induced a clear difference in the chirality of the product: (R)-ibuprofen enhanced the formation of (S)-styrene oxide, whereas (S)-ibuprofen preferentially afforded (R)-styrene oxide. The crystal structure of an (R)-ibuprofen-bound cytochrome P450(SPα) (resolution 1.9 Å) revealed that the carboxylate group of (R)-ibuprofen served as an acid-base catalyst to initiate the epoxidation. A docking simulation of the binding of styrene in the active site of the (R)-ibuprofen-bound form suggested that the orientation of the vinyl group of styrene in the active site agreed with the formation of (S)-styrene oxide.
在羧酸作为诱饵分子的存在下，H(2)O(2)依赖性细胞色素 P450(SPα)催化了苯乙烯的立体选择性环氧化。苯乙烯氧化物的立体选择性可以通过诱饵分子的性质来改变。特别是，诱饵分子的α-位的手性诱导了产物手性的明显差异：(R)-布洛芬增强了(S)-苯乙烯氧化物的形成，而(S)-布洛芬则优先提供(R)-苯乙烯氧化物。(R)-布洛芬结合细胞色素 P450(SPα)的晶体结构(分辨率为 1.9 Å)表明，(R)-布洛芬的羧酸盐基团充当酸碱催化剂以引发环氧化。在(R)-布洛芬结合形式的活性位点中苯乙烯结合的对接模拟表明，苯乙烯的乙烯基基团在活性位点中的取向与(S)-苯乙烯氧化物的形成一致。
