光谱法研究异烟肼与牛血清白蛋白的相互作用

采用荧光光谱研究了异烟肼与牛血清白蛋白（BSA）的相互作用。异烟肼对BSA的荧光有较强的猝灭作用。根据研究292K，511K温度下异烟肼对BSA的荧光猝灭光谱，发现异烟肼对BSA的荧光猝灭属于动态猝灭过程，根据Frster非辐射能量转移理论计算出异烟肼与BSA间的结合距离r=5．60nm，结合常数（Kb）分别为5．；521X10^4 L·mol～（202K），5．189X104L·mol。（31lK），通过计算热力学数据焓变△rHm=-20．；545kJ·mol^-1，熵变△rSm=20．8J·mol^-1表明二者主要靠静电引力结合，采用同步荧光光谱探讨了异烟肼对BSA构象的影响。  

牛血清蛋白-Au配合物及其复合物制备及表征

以牛血清蛋白（bovine serum albumin，BSA）、氯金酸（HAuCl₄）、NaOH等为原料，采用一锅合成法制备了牛血清蛋白-Au配合物（BSA-Au），观察到了样品的宽带红光荧光发射。通过库仑力作用将BSA-Au与表面带有正电荷的金纳米颗粒进行复合，对纳米复合物的吸收光谱及荧光光谱特性进行了研究。实验结果表明，在本实验条件下，金纳米颗粒虽然增强了复合物样品在可见光区域的光吸收，但对BSA-Au红光发光有猝灭作用。  

Characterization of the interaction between bovine serum albumin and doxycycline by chemiluminescence and molecular docking

The interaction of bovine serum albumin with doxycycline was investigated using chemiluminescence and molecular docking. Doxycycline at concentrations from 1.0 to 2.5 × 10³ pmol · L⁻¹ quenched the chemiluminescence from the luminol–bovine serum albumin system. The data were analyzed using a chemiluminescence mathematic model for protein–ligand interaction, log[(I₀ – I)/I] = logK + nlog[D]. The binding constant of bovine serum albumin with doxycycline was 3.36 × 10⁵ L · mol⁻¹ at 298 K with one binding site. The binding constant, enthalpy change, entropy change, and binding free energy change showed that the bonding of doxycycline to bovine serum albumin was spontaneous and enthalpy driven via hydrogen bonding and van der Waals forces. Further molecular docking analysis substantiated that doxycycline was well positioned in the pocket at the subdomain IIA (site I) of bovine serum albumin with a binding constant of 3.31 × 10⁵ L · mol⁻¹. Doxycycline served as both a hydrogen acceptor and donor and mainly interacted with the Arg217 residue through four hydrogen bonds with an average length of 2.55 Å. The chemiluminescence mechanism of doxycycline on luminol–bovine serum albumin system was evaluated, showing that a ternary complex of luminol–bovine serum albumin–doxycycline was formed with luminol and doxycycline at sites III and I of bovine serum albumin.