Yang Qinqin, Liang Jiangong, Han Heyou
College of Science, State Key Laboratory of Agricultural Microbiology, Institute of Chemical Biology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
J Phys Chem B. 2009 Jul 30;113(30):10454-8. doi: 10.1021/jp904004w.
The interaction of magnetic iron oxide nanoparticles (MNPs) with bovine serum albumin (BSA) was investigated by fluorescence (FL), ultraviolet visible (UV-vis) absorption, Raman, and circular dichroism (CD) spectroscopy. Results indicated that MNPs quench BSA FL mainly by a static quenching mechanism. The FL quenching constants KSV were obtained as 2.44x10(8), 2.41x10(8), and 2.40x10(8) L.mol(-1) at 291, 298, and 313 K, respectively. The thermodynamic parameters of enthalpy change DeltaH(theta), entropy change DeltaS(theta), and free energy change DeltaGtheta were -0.90 kJ.mol(-1), 157.38 J.mol(-1).K(-1), and -47.80 kJ.mol(-1) (298 K), respectively. The association constant (KA) and the number of binding sites (n) were 7.64x10(7) L.mol(-1) and 46.55 at higher concentration of MNPs, and 1.35x10(6) L.mol(-1) and 284.74 at lower concentration of MNPs. The analysis results suggested that the interaction was spontaneous and the electrostatic interactions played key roles in the reaction process. In addition, the Raman and CD spectra proved secondary structure alteration of BSA in the presence of MNPs.
通过荧光（FL）、紫外可见（UV-vis）吸收、拉曼和圆二色性（CD）光谱研究了磁性氧化铁纳米颗粒（MNPs）与牛血清白蛋白（BSA）的相互作用。结果表明，MNPs主要通过静态猝灭机制猝灭BSA的荧光。在291、298和313 K时，荧光猝灭常数KSV分别为2.44×10⁸、2.41×10⁸和2.40×10⁸ L·mol⁻¹。焓变ΔH⁰、熵变ΔS⁰和自由能变ΔG⁰的热力学参数分别为-0.90 kJ·mol⁻¹、157.38 J·mol⁻¹·K⁻¹和-47.80 kJ·mol⁻¹（298 K）。在较高浓度的MNPs下，结合常数（KA）和结合位点数量（n）分别为7.64×10⁷ L·mol⁻¹和46.55，在较低浓度的MNPs下分别为1.35×10⁶ L·mol⁻¹和284.74。分析结果表明，该相互作用是自发的，静电相互作用在反应过程中起关键作用。此外，拉曼光谱和CD光谱证明了在MNPs存在下BSA的二级结构发生了改变。
