Sarquis J L, Adams E T
Biophys Chem. 1976 Mar;4(2):181-90. doi: 10.1016/0301-4622(76)85008-9.
The self-association of beta-lactoglobulin C at pH 4.65 (23 degrees C) in acetate buffer has been studied at various temperatures, 10, 16, 20 and 25 degrees C, by a series of sedimentation equilibrium experiments. Two different buffers were used. Buffer I with an ionic strength of 0.1 consisted of 0.1M acetic acid and 0.1M sodium acetate; buffer II had 0.1M KCl in addiation so that its ionic strength was 0.2. The variation of the apparent weight average molecular weight, Mwa, with the total solute concentration, c, was characteristic of a self-association. In contrast to the behavior of beta-lactoglobulin A in acetate buffer, the association of beta-lactoglobulin C did not proceed beyond dimer. Furthermore, within the experimental error, the self-association of beta-lactoglobulin C was independent of temperature and ionic strength; all experimental data could be put on the same Mwa (or M1/Mwa) vs. c plot! Several models were used to test the self-association, and a monomer--dimer association with K2 = 2.10 X 10(3) dl/g and BM1 =- 1.2 X 10(-2) dl/g seemed to give a good description of the M1/Mwa vs. c curve.
通过一系列沉降平衡实验，研究了β-乳球蛋白C在pH 4.65（23℃）的醋酸盐缓冲液中于10、16、20和25℃等不同温度下的自缔合情况。使用了两种不同的缓冲液。离子强度为0.1的缓冲液I由0.1M醋酸和0.1M醋酸钠组成；缓冲液II除含有0.1M醋酸和0.1M醋酸钠外，还含有0.1M KCl，因此其离子强度为0.2。表观重均分子量Mwa随总溶质浓度c的变化具有自缔合的特征。与β-乳球蛋白A在醋酸盐缓冲液中的行为不同，β-乳球蛋白C的缔合不会超过二聚体。此外，在实验误差范围内，β-乳球蛋白C的自缔合与温度和离子强度无关；所有实验数据都可以绘制在同一张Mwa（或M1/Mwa）对c的图上！使用了几种模型来测试自缔合情况，一种K2 = 2.10×10³ dl/g且BM1 = -1.2×10⁻² dl/g的单体-二聚体缔合似乎能很好地描述M1/Mwa对c的曲线。
