荧光光谱法研究20(S)-原人参三醇与牛血清白蛋白的相互作用

用荧光光谱和紫外-可见吸收光谱研究了20(S)-原人参三醇(PPT)与牛血清白蛋白(BSA)的相互作用，结果表明：PPT对BSA荧光的猝灭类型为静态猝灭。在温度为298，308，318 K时的结合常数分别是0.926 3×103，0.618 2×103，0.414 4×103 L·mol-1，结合位点均接近于1。PPT与BSA结合过程中主要的驱动力为氢键和范德华力。与PPT结合后，BSA分子中色氨酸残基部位的结构变得更加紧密。依据Fster的荧光共振能量转移理论得出PPT与BSA的结合距离r为2.62 nm，能量转移效率E为0.32。

Fluorescence Spectroscopic Studies on Binding of 20 (S)-Protopanaxatriol with Bovine Serum Albumin

The interaction between 20(S)-protopanaxatriol (PPT) and bovine serum albumin ( BSA) was studied with fluorescence quenching technique and ultra-violet absorption spectroscopy. The results indicated that PPT led to the intrinsic fluorescence quenching of BSA through a static quenching process .The binding constants of PPT with BSA obtained with fluorescence quenching method were calculated as 0.926 3×103 (298 K), 0.618 2×103 (308 K), 0.414 4×103 L·mol-1(318 K), respectively; while the number binding sites n were close to unity. The results showed that the driving force of the interaction between PPT and BSA was hydrogen bond and Van der Waals force. The result of synchronous fluorescence spectra showed that binding of PPT with BSA could induce conformational changes in BSA, that the part of tryptophan became more closely. According to Fster fluorescence resonance energy transfer theory, the binding distance r and energy-transfer efficiency E were respectively 26.2 nm and 0.32.