Ingham K C, Saroff H A, Edelhoch H
Biochemistry. 1975 Oct 21;14(21):4745-51. doi: 10.1021/bi00692a028.
The self-association of human luteinizing hormone (hLH) is enhanced in the presence of 8-anilino-1-naphthalenesulfonate (ANS). Sedimentation equilibrium measurements indicate that the hormone exists primarily as a dimer in the presence of excess ANS. It is shown that, for a self-associating protein system in which monomer and dimer have different affinities and/or capacities for ligand, both the shape and the position of the binding curve depend on protein concentration. Gel filtration and fluorescence measurements indicate that the hLH dimer has a single high affintiy site (K greater than 10(6) M-1) for ANS while binding to the monomer is too weak to be observed. This leads to negative cooperativity in the binding and to a shift of the binding curve to lower free ligand concentration with increasing concentration of the hormone.
在8-苯胺基-1-萘磺酸盐（ANS）存在的情况下，人促黄体生成素（hLH）的自缔合作用增强。沉降平衡测量表明，在过量ANS存在时，该激素主要以二聚体形式存在。结果表明，对于一个自缔合蛋白质系统，其中单体和二聚体对配体具有不同的亲和力和/或结合能力，结合曲线的形状和位置都取决于蛋白质浓度。凝胶过滤和荧光测量表明，hLH二聚体对ANS有一个单一的高亲和力位点（K大于10⁶ M⁻¹），而与单体的结合太弱以至于无法观察到。这导致结合过程中的负协同效应，并随着激素浓度的增加使结合曲线向更低的游离配体浓度方向移动。
