放射性示踪法研究结合希土的四膜虫膜蛋白——Ⅱ.镱结合膜蛋白的性质

A RADIOTRACER STUDY OF RARE EARTH BINDING MEMBRANE PROTEIN OF TETRAHYMENA PYRIFORMIS. Ⅱ, PROPERTIES OF Yb BINDING MEMBRANE PROTEIN

摘要: 本文从四膜虫分离得到了一定量的镱结合膜蛋白並测定了它的摩尔消光系数。由平衡渗透法及Scatchard类型图,测得该镱-膜蛋白络合物解离常数和结合数的平均值分别为(4.2±0.1)×10~(-6)Smol/l和3,4±0.7,即此络合物的表观稳定常数为2.4×10~5l/mol,或IgK_(?)=5.4.对镱结合膜蛋白及无镱结合膜蛋白氨基酸组分的分析表明,二者之间无明显区别。

Abstract: Yb binding membrane protein of tetrahymena pyriformis was isolated in considerable amount.The average dissociation constant and the average binding site number of the Yb-protein complex were determined as (4.2±0.1)×10~(-6) mol/l and 3.4±0.7 respectively by equilibrium dialysis experiment and concomitant Scatchard-type diagram.Hence, the apparent stability constant of this complex is around 2.4x10~5l/mol, or 1gK=5.4.No apparent difference on the aminoacid composition between Yb binding protein and corresponding non-Yb binding protein was observed.