Fried Stephen D, Boxer Steven G
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Science. 2015 Aug 28;349(6251):936. doi: 10.1126/science.aab1627. Epub 2015 Aug 27.
Natarajan et al. and Chen and Savidge comment that comparing the electric field in ketosteroid isomerase's (KSI's) active site to zero overestimates the catalytic effect of KSI's electric field because the reference reaction occurs in water, which itself exerts a sizable electrostatic field. To compensate, Natarajan et al. argue that additional catalytic weight arises from positioning of the general base, whereas Chen and Savidge propose a separate contribution from desolvation of the general base. We note that the former claim is not well supported by published results, and the latter claim is intriguing but lacks experimental basis. We also take the opportunity to clarify some of the more conceptually subtle aspects of electrostatic catalysis.
纳塔拉詹等人以及陈和萨维奇评论称，将酮甾类异构酶（KSI）活性位点的电场与零进行比较会高估KSI电场的催化作用，因为参考反应发生在水中，而水本身会施加相当大的静电场。为了进行补偿，纳塔拉詹等人认为额外的催化权重源于一般碱的定位，而陈和萨维奇则提出一般碱去溶剂化会有单独的贡献。我们注意到前一种说法没有得到已发表结果的有力支持，而后一种说法很有趣但缺乏实验依据。我们还借此机会澄清了静电催化在概念上一些更为微妙的方面。
