头孢噻肟钠与牛血清蛋白相互作用的光谱特征

用光谱法研究头孢噻肟钠（CS）和牛血清蛋白（BSA）在模拟生命体生理条件下相互作用的特征.结果表明CS主要以静态猝灭方式使BSA的荧光强度显著降低；利用同步荧光法研究了CS和BSA作用后牛血清蛋白的构象发生了变化；求得不同温度下二者的结合常数和结合位点数,探讨了微量金属离子对实验体系结合常数的影响,并根据热力学参数确定了CS和BSA之间主要依靠静电力结合.根据Froester非辐射能量转移机理,测定了CS与BSA相互结合时的作用距离2.56nm,表明BSA与CS之间发生了非辐射能量转移.

Spectral Characteristics of the Interaction Between Cefotaxime Sodium (CS) and Bovine Serum Albumin (BSA)

The binding interaction between cefotaxime sodium（CS） and bovine sserum albumin （BSA） was investigated by fluorescence spectra. Synchronous fluorescence spectra were used to study the structure change of BSA with the addition of CS. In physiological condition （pHT. 4） ,CS led to the increasing of UV absorption and the quenching of intrinsic fluorescence of BSA. The Stern-Volmer curve shows that the quenching of CS to BSA is probably a single static quenching process. The binding sites number n and apparent binding constant K were measured at 25℃ and 37;C and the effect of different ions on the binding constant of CTS-BSA was gained. The distance （r= 2.56nm） between donor （BSA） and acceptor （CS） was obtained according to Froester theory of non-radiation energy transfer. The thermodynamic parameters AH, AG and AS at different temperature were calculated, respectively,which indicated that electrostatic force played a major role in the interaction of CS with BSA.