不同pH下人血清白蛋白热变性及结构可逆性研究

Study on Thermal Stability of Human Serum Albumin at Different p H Values and Its Structural Reversibility

本文通过用差示扫描量热法(DSC)、动态光散射(DLS)和圆二色谱(CD)检测不同p H下人血清白蛋白(HSA)的结构,并观察其随p H变化的可逆性,以探讨不同p H对HSA结构的影响及HSA结构在p H变化下的可逆性。结果表明,p H7.0条件下HSA的热稳定性最好,热变性温度(Tm)为68.17±0.06℃,不同p H条件下HSA三级结构均发生了一定程度的改变,酸性和碱性条件下的HSA调回p H7.0后变性温度接近于p H7.0条件下的Tm值。不同p H条件下的粒径相对于p H7.0条件下增大,调回p H7.0后减小。CD实验表明了p H对HSA二级结构的影响。HSA结构在不同p H下调回中性条件时会重新折叠,但不能恢复中性条件下的结构状态。

The tertiary structure of human serum albumin（ HSA） and the structure-reversibility at different p H values had been studied by DSC,DLS and CD. The results indicated that HSA proves to be the most stable structure at p H 7. 0,and the melting temperature（ Tm） is 68. 17 ± 0. 06℃. The tertiary structure of HSA is changed at different p H values and the Tmof HSA is very close to the Tmat p H 7. 0 when p H is adjusted back to 7. 0 from different p H values. The size of HSA is larger at other different p H values than that at p H 7. 0 and it gets smaller when p H is adjusted back to 7. 0. The influence of p H on the secondary structure of HSA is detected by CD.Although HSA can be refolded when adjusted back to 7. 0 from different p H values,it can’t return back to the structure of HSA at p H 7. 0.