Phelps C, Antonini E, Brunori M
Biochem J. 1972 Jun;128(2):377-82. doi: 10.1042/bj1280377.
The equilibrium and kinetics of ethyl isocyanide binding to ferroperoxidase were studied. At pH9.1 the results of both studies are consistent with a single-process model with an affinity constant of 95m(-1) and combination and dissociation constants of 2.2x10(3)m(-1).s(-1) and 23s(-1) respectively. Ethyl isocyanide is not bound significantly at pH values lower than 6.0, and in this behaviour and the pH-dependence of the affinity constant, similarities exist between isocyanide and cyanide binding. The enthalpy of the process measured by equilibrium methods is -59kJ/mol (-14kcal/mol). At pH values below 9, the ethyl isocyanide adduct changes in a slow time-dependent manner, giving rise to a new species. These changes are reversible on increasing the pH. The results are discussed in relation to other known information about ligand binding to ferroperoxidase and to myoglobin.
研究了乙基异氰化物与铁过氧化物酶结合的平衡和动力学。在pH9.1时，两项研究的结果均与单过程模型一致，亲和常数为95m⁻¹，结合常数和解离常数分别为2.2×10³m⁻¹·s⁻¹和23s⁻¹。在低于6.0的pH值下，乙基异氰化物的结合不明显，并且在这种行为以及亲和常数的pH依赖性方面，异氰化物和氰化物的结合存在相似性。通过平衡方法测得的该过程的焓为-59kJ/mol（-14kcal/mol）。在pH值低于9时，乙基异氰化物加合物以缓慢的时间依赖性方式发生变化，产生一种新的物质。这些变化在提高pH值时是可逆的。结合关于配体与铁过氧化物酶和肌红蛋白结合的其他已知信息对结果进行了讨论。
