Nakatani H, Morita T, Hiromi K
Biochim Biophys Acta. 1978 Aug 7;525(2):423-8. doi: 10.1016/0005-2744(78)90238-3.
Benzeneboronic acid, a transition-state analog for serine proteases, binds to the catalytic center of subtilisin BPN'. The binding mechanism is so-called two-step mechanism; the initial fast association followed by a slow unimolecular process (Nakatani, H., Uehara, Y. and Hiromi, K. (1975) J. Biochem. (Tokyo) 77, 615--616), E + S fast equilibrium ES slow equilibrium ES (E = subtilisin, S = benzenebroonic acid). The structure of the transient complex (ES) at the initial association process was manifested by the substituent effect of benzeneboronic acid on the rate parameters in the elementary processes. The study by the temperature-junp and stopped-flow methods showed that the boron atom in benzeneboronic acid strongly interacts with a nucleophilic site, probably, O gamma of Ser-221 or imidazole of His-64 at the catalytic center, already at the initial fast association.
苯硼酸作为丝氨酸蛋白酶的过渡态类似物，可与嗜热栖热菌蛋白酶BPN'的催化中心结合。其结合机制为所谓的两步机制：最初是快速缔合，随后是缓慢的单分子过程（中谷浩、上原洋和广见健一，《生物化学杂志》（东京），1975年，第77卷，第615 - 616页），E + S快速平衡⇌ES缓慢平衡⇌ES（E = 嗜热栖热菌蛋白酶，S = 苯硼酸）。初始缔合过程中瞬态复合物（ES）的结构通过苯硼酸对基本过程中速率参数的取代基效应得以体现。通过温度跃变和停流方法进行的研究表明，在初始快速缔合阶段，苯硼酸中的硼原子就已与催化中心处的亲核位点（可能是Ser - 221的Oγ或His - 64的咪唑）发生强烈相互作用。
