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首次采用共振光散射、荧光光谱并结合平衡透析法研究了 I- 与人血清白蛋白 ( human serum albumin,简称 HSA)或牛血清白蛋白 ( Bovine Serum Albumin,简称 BSA)结合平衡。首次观测到 I- 对 HSA和 BSA的共振光散射有增强效应 ,却导致 35 0和 70 0 nm处的荧光淬灭。平衡透析的结果表明 :I- 与 HSA或 BSA的结合平衡不适合用 Scatchard模型处理 ,却能较好地符合相平衡分配规律 ,表观相分配常数数量级为 1 0 4。Cl-很可能是通过改变溶液的离子强度影响 I- 的结合。根据不同的 p H条件下的透析结果 ,推测 I- 是与白蛋白上质子化的碱性氨基酸残基结合。
The binding equilibrium between I- and human serum albumin (HSA) or bovine serum albumin (BSA) was studied for the first time using resonance light scattering, fluorescence spectroscopy and equilibrium dialysis. It was first observed that I-enhanced resonance light scattering of HSA and BSA resulted in fluorescence quenching at 35 0 and 70 0 nm. The results of equilibrium dialysis showed that the binding equilibrium of I-with HSA or BSA was not suitable for the treatment with Scatchard model, but it was in good agreement with the law of phase equilibrium distribution. The apparent phase assignment constant was of the order of 104. Cl- probably affects the I- binding by changing the ionic strength of the solution. Based on the different dialysis results under p H, it is speculated that I- is bound to a protonated basic amino acid residue on albumin.