Hanai K
J Biochem. 1976 Sep;80(3):491-5. doi: 10.1093/oxfordjournals.jbchem.a131303.
The interaction of chymotrypsinogen A with benzeneboronic acid (BBA), a transition state along inhibitor of serine proteases, was investigated by the temperature-jump method using pH indicators. It was found that l/tau is dependent on BBA concentration, in contrast to the case of the alpha-chymotrypsin [EC 3.4.21.1]-BBA system in which l/tau is independent of BBA concentration. By examination of the pH dependences of the kinetic parameters, the acid dissociation behavior of His 57 in chymotrypsinogen, chymotrypsinogen-trigonal BBA complex and chymotrypsinogen-tetrahedral BBA complex was analyzed. The kinetic deuterium isotope effect was also examined and found to occur principally on the acid dissociation constants. The state of the catalytic residues in the zymogen molecule is discussed based on these results.
使用pH指示剂通过温度跃升法研究了胰凝乳蛋白酶原A与苯硼酸（BBA，一种丝氨酸蛋白酶的过渡态抑制剂）的相互作用。结果发现，与α-胰凝乳蛋白酶[EC 3.4.21.1]-BBA体系（其中1/τ与BBA浓度无关）不同，1/τ取决于BBA浓度。通过研究动力学参数的pH依赖性，分析了胰凝乳蛋白酶原、胰凝乳蛋白酶原-三角BBA复合物和胰凝乳蛋白酶原-四面体BBA复合物中His 57的酸解离行为。还研究了动力学氘同位素效应，发现其主要发生在酸解离常数上。基于这些结果讨论了酶原分子中催化残基的状态。
