De Novo design and utilization of photolabile caged substrates as probes of hydrogen tunneling with horse liver alcohol dehydrogenase at sub-zero temperatures: a cautionary note
作者:Shiou-Chuan Tsai、Judith P. Klinman
DOI:10.1016/s0045-2068(03)00018-x
日期:2003.4
Biochemistry, 40 (2001) 2303]. A strategy was therefore undertaken to reduce kinetic complexity at sub-zero temperatures, using a photolabile (caged) benzyl alcohol that prebinds to the enzyme and yields the active substrate upon photolysis. By computer modeling, a series of caged alcohols were designed de novo, synthesized, and characterized with regard to photolysis and binding properties. The o-nitrobenzyl
为了了解蛋白质动力学对酶催化和氢隧穿的影响,在零以下温度下研究了马肝醇脱氢酶(HLADH)催化苯甲醇的氧化。先前的研究表明,由于缓慢的结合和底物的损失,野生型HLADH在低至-50摄氏度时具有显着的动力学复杂性[S.-C。蔡,JP Klinman,生物化学,40(2001)2303]。因此,采取了一种策略,使用预先结合到酶上并在光解时产生活性底物的光不稳定(笼养)苄醇,以降低在零以下温度下的动力学复杂性。通过计算机建模,从头开始设计,合成了一系列笼蔽的醇,并就光解和结合特性进行了表征。具有独特长尾的邻硝基苄基醚15 被发现是最理想的。在低于零温度的50%MeOH中,观察到两相动力学曲线,并通过使用15提高了速率。尽管消除了底物结合作为限速步骤,但使用笼蔽的苯甲醇并不能产生可测量的H / D动力学同位素效应。出乎意料的是,基于底物对酶的化学计量,观察到的快速相对应于多种酶转换。可能的副反应及