硫酸头孢匹罗与牛血清白蛋白结合反应的发光机理

Luminescence Mechanism Study of The Conjugation Reaction between Cefpirome Sulfate and Bovine Serum Albumin

在人生理条件下,利用荧光猝灭法、同步荧光法及共振光散射法,分别研究了不同温度下硫酸头孢匹罗(CPS)与牛血清白蛋白(BSA)间的结合反应。结果表明:随着CPS浓度的增加,BSA的荧光、共振散射光依次降低,其荧光猝灭为静态猝灭过程并伴随非辐射能量转移作用。反应的结合常数为104数量级,结合位点数约为1;结合位点位于BSA的亚结构ⅡA中;结合距离r<7 nm。CPS与BSA间作用力主要是静电引力;Hill系数nH<1,表明CPS有弱的负协同作用。同步荧光光谱表明CPS对BSA构象产生影响,使BSA腔内疏水环境的极性增强,疏水性减弱。

In human physical conditions,the binding reaction between cefpirome sulfate（CPS） and bovine serum albumin（BSA） was investigated by fluorescence spectroscopy,synchronous fluorescence spectroscopy and resonance light scattering（RLS） at different temperatures.Results showed that both fluorescence and RLS of BSA reduced with the increased concentration of CPS,and the effect between CPS and BSA was static fluorescence quenching process with Frester spectroscopy energy transfer.The scope of apparent binding constants（Ka） was ~104;the corresponding binding site value（n） in the binary systems was 1;the binding distances（r） were much smaller than 7 nm and the primary binding site for CPS was located at site Ⅰ in sub-domain ⅡA of BSA.Besides,the electrostatic attraction plays an important role in the conjugation reaction of BSA and CPS.The values of Hill＇s coefficients were less than 1,which indicated that there was some negative cooperative effect.Studies utilizing synchronous spectra showed that the conjugation reaction between CPS and BSA would affect the conformation of BSA,leading to the polarity around BSA strengthened and the hydrophobicity weakened.