Gent W L, Wilson B D
Pharmacology Department, University of Stellenbosch Medical School, Tygerberg, Republic of South Africa.
Biochem Pharmacol. 1989 Jan 15;38(2):343-6. doi: 10.1016/0006-2952(89)90047-6.
Ionization characteristics of L-3,5-di-iodotyrosine have been measured under various conditions. These data, which correct an erroneous report of pK3 in the literature, have been used to estimate the ionization constants of the thyroid hormone L-3',3,5-tri-iodothyronine (T3). On this basis a reinterpretation has been made of the pH-dependent binding of the hormone to its solubilized rat liver nuclear receptor (Wilson BD and Gent WL, Biochem J 232: 663-667, 1985). The interaction may depend on the ionization of the phenolic group of T3 and an acidic group (pK'7.6) in the receptor site, leading to the formation of a hydrogen bond between the two groups. The changes of the number of binding sites with pH must then result independently from alterations in the conformation of the receptor protein.
已在各种条件下测量了L-3,5-二碘酪氨酸的电离特性。这些数据纠正了文献中关于pK3的错误报告，并已用于估算甲状腺激素L-3',3,5-三碘甲状腺原氨酸（T3）的电离常数。在此基础上，对该激素与溶解的大鼠肝核受体的pH依赖性结合进行了重新解释（Wilson BD和Gent WL，《生物化学杂志》232: 663 - 667, 1985）。这种相互作用可能取决于T3酚基和受体位点中一个酸性基团（pK'7.6）的电离，从而导致这两个基团之间形成氢键。结合位点数量随pH的变化必定独立于受体蛋白构象的改变。
