Direct hydroxylation of primary carbons in small alkanes by wild-type cytochrome P450BM3 containing perfluorocarboxylic acids as decoy molecules
Direct hydroxylation of primary carbons in small alkanes by wild-type cytochrome P450BM3 containing perfluorocarboxylic acids as decoy molecules
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DOI：
10.1039/c3sc50378j
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Watanabe, Yoshihito
中科院分区：
文献类型：
--
作者：
Kawakami, Norifumi;Shoji, Osami;Watanabe, Yoshihito
细胞色素 P450BM3 (P450BM3) 是一种长烷基链脂肪酸羟化酶，在产物形成方面表现出极高的催化周转率和 NADPH 的高偶联效率（产物形成率/NADPH 消耗率）。尽管 P450BM3 专门羟基化长烷基链脂肪酸，但我们发现简单添加全氟羧酸 (PF) 作为惰性虚拟底物（诱饵分子）即可将 P450BM3 转变为小型烷烃羟化酶。例如，PF 结合的 P450BM3 将丙烷和丁烷分别氧化为 2-丙醇和 2-丁醇。然而，与长烷基链脂肪酸羟基化相比，小烷烃羟基化的偶联效率非常低。在本研究中，我们研究了小烷烃羟基化的实验条件，以提高偶联效率并实现其伯碳的羟基化。为了提高反应混合物中气态底物的浓度，我们在0.5 MPa小烷烃的高压条件下进行反应。高压条件下丙烷羟基化显着提高了偶联效率至48%。此外，还生成了在低压条件下从未观察到的1-丙醇。值得注意的是，在0.5 MPa的压力条件下，乙烷羟基化过程中观察到可检测到的乙醇量，而甲烷则没有羟基化。这些结果表明，通过增加小烷烃的浓度，“P450BM3-诱饵分子系统”可以催化小烷烃中伯碳的羟基化反应。
Cytochrome P450BM3 (P450BM3) is a long-alkyl-chain fatty acid hydroxylase that shows an extremely high catalytic turnover rate and high coupling efficiency of NADPH for product formation (product formation rate per NADPH consumption rate). Although P450BM3 exclusively hydroxylates long-alkyl-chain fatty acids, we have found that simple addition of perfluorocarboxylic acids (PFs) as inert dummy substrates (decoy molecules) turns P450BM3 into a small alkane hydroxylase. For example, PF-bound P450BM3 oxidizes propane and butane to 2-propanol and 2-butanol, respectively. The coupling efficiency of small alkane hydroxylation, however, is very low compared with that of long-alkyl-chain fatty acid hydroxylation. In this study, we examined the experimental conditions for small alkane hydroxylation in an effort to improve the coupling efficiency and to realize the hydroxylation of their primary carbons. To increase the concentration of gaseous substrates in the reaction mixture, we performed reactions under the high-pressure condition of 0.5 MPa small alkanes. Propane hydroxylation under high-pressure conditions significantly improved the coupling efficiency to 48%. Furthermore, 1-propanol, which has never been observed under lower-pressure conditions, was produced. It is noteworthy that a detectable amount of ethanol was observed in the ethane hydroxylation under the pressure condition of 0.5 MPa, whereas methane was not hydroxylated. These results indicate that by increasing the concentration of small alkanes, the "P450BM3-decoy molecule system" can catalyze hydroxylation reactions of the primary carbons in small alkanes.