Institute of Biochemistry and Biophysics, University of Tehran. Tehran, Iran.
J Biomol Struct Dyn. 2011 Oct;29(2):283-96. doi: 10.1080/07391102.2011.10507385.
The pharmacokinetics and pharmacodynamics of any drug will depend, largely, on the interaction that has with human serum albumin (HSA), the most abundant plasma protein. The interaction between newly synthesized Pd(II) complexe, 2,2'-bipyridin Butylglycinato Pd(II) nitrate, an anti-tumor component, with HSA was studied at different temperatures by fluorescence, far UV circular dichroism (CD), UV-visible spectrophotometry and theoretical approaches. The Pd(II) complex has a strong ability to quench the intrinsic fluorescence of HSA through a dynamic quenching procedure. The binding parameters and thermodynamic parameters, including δH°, δS° and δG° were calculated by fluorescence quenching method, indicated that hydrophobic forces play a major role in the interaction of Pd(II) complex with HSA. Based on Autodock, FRET (fluorescence resonance energy transfer) and fluorescence quenching data, it may be concluded that one of the binding sites in the complex of HSA is near the only one Trp of HSA (Trp214) in sub domain IIA of the protein. Far-UV-CD results indicated that Pd(II)-complex induced increase in the α-helical content of the protein. The anti-tumor property of the synthesized Pd(II) complex was studied by testing it on human tumor cell line K562. The 50% cytotoxic concentration (Cc₅₀) of complex was determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Also, fluorescence staining with DAPI (4,6-diamidino-2-phenylindole) revealed some typical nuclear changes that are characteristic of apoptosis which is induced at Cc₅₀ concentration of Pd(II) complex in K562 cell line after 24 h incubation. Our results suggest that Pd(II) complex is a promising anti-proliferative agent and should execute its biological effects by inducing apoptosis.
任何药物的药代动力学和药效学在很大程度上取决于其与人体血清白蛋白（HSA）的相互作用，HSA 是最丰富的血浆蛋白。通过荧光、远紫外圆二色性（CD）、紫外-可见分光光度法和理论方法研究了新合成的 Pd(II)配合物 2,2'-联吡啶丁基甘氨酸合硝酸钯(II)（一种抗肿瘤成分）与 HSA 在不同温度下的相互作用。Pd(II)配合物通过动态猝灭过程具有强烈的猝灭 HSA 固有荧光的能力。荧光猝灭法计算了结合参数和热力学参数，包括δH°、δS°和δG°，表明疏水力在 Pd(II)配合物与 HSA 的相互作用中起主要作用。基于 Autodock、FRET（荧光共振能量转移）和荧光猝灭数据，可以得出结论，HSA 结合位点之一位于蛋白质亚域 IIA 中 HSA 的唯一色氨酸（Trp214）附近。远紫外 CD 结果表明，Pd(II)-配合物诱导蛋白质α-螺旋含量增加。通过在人肿瘤细胞系 K562 上测试合成的 Pd(II)配合物来研究其抗肿瘤特性。使用 MTT（3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴盐）测定法测定复合物的 50%细胞毒性浓度（Cc₅₀）。此外，用 DAPI（4,6-二脒基-2-苯基吲哚）荧光染色显示了一些典型的核变化，这些变化是凋亡的特征，在 K562 细胞系中，Pd(II)配合物在 Cc₅₀浓度下孵育 24 小时后诱导凋亡。我们的结果表明，Pd(II)配合物是一种有前途的抗增殖剂，应该通过诱导凋亡来发挥其生物学效应。
