Hydrogen exchange rates in pancreatic trypsin inhibitor are not correlated to thermal stability in urea.
Hydrogen exchange rates in pancreatic trypsin inhibitor are not correlated to thermal stability in urea.
复制标题
胰蛋白酶抑制剂中的氢交换率与尿素的热稳定性不相关。
DOI：
10.1021/bi00519a027
复制
发表时间：
1981
期刊：
影响因子：
2.9
通讯作者：
Woodward,CK
中科院分区：
文献类型：
--
作者：
Hilton,BD;Trudeau,K;Woodward,CK
摘要：已报道了牛胰酶抑制物(BPTI)的单肽氨基NH质子的氢同位素交换率。我们将BPTI单质子交换率的复杂的pH和温度依赖性解释为两个不同温度依赖性的过程之间机制的变化[Hilton，B.D.，&Woodward，C.K.(1979)BioChemical 18,5834；Woodward，C.K.，&Hilton，BD(1980)BiPhys。J.32,561]。一个过程的特征是活化能为20-35千卡/摩尔，涉及允许内部质子交换的折叠状态的运动。第二个过程的活化能约为65kcal/mol，对应于主要的合作展开。这个双过程模型解释了最慢交换质子动力学中与pH和温度相关的所有不寻常的特征，并从根本上不同于Wothrich&Wagner(1979)[Wothrich，K“&Wagner，G.(1979)/]对相同数据的解释。摩尔。比奥尔。130，1]。例如，在双过程模型中，高活化能交换剂的特性不能归因于
Bruce D. Hilton, 1 Kathleen Trudeau, and Clare K. Woodward* abstract: The hydrogen-isotope exchange rates of single, assigned peptide amide NH protons havebeen reported for bovine pancreatic trypsin inhibitor (BPTI). We have interpreted the complex pH and temperature dependence of the single proton exchange rates of BPTI as arising from changes in the mechanism between two processes that differ in tem-perature dependence [Hilton, B. D., & Woodward, C. K.(1979) Biochemistry 18, 5834; Woodward, C. K., & Hilton, BD (1980) Biophys. J. 32, 561]. One process, characterized by an activation energy of 20-35 kcal/mol, involves motions of the folded state that allow exchange of interior protons. The second process, characterized by an activation energy of~ 65 kcal/mol, corresponds to major, cooperative unfolding. This two-process model explains all of the unusual features of the pH and temperature dependence of the kinetics of the slowest exchanging protons and differs fundamentally from the interpretation of the same data by Wuthrich & Wagner (1979)[Wuthrich, K „& Wagner, G.(1979)/. Mol. Biol. 130, 1]. For example, in the two-process model, characteristics of the high activation energy exchangerates cannot be ascribed to