College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022, China.
J Photochem Photobiol B. 2012 Dec 5;117:126-31. doi: 10.1016/j.jphotobiol.2012.09.007. Epub 2012 Oct 8.
The binding of sinomenine to human serum albumin (HSA) in aqueous solution in the absence and presence of urea has been studied by fluorescence and the three-dimensional (3D) fluorescence at pH 7.40. Subdomain IIA binding site of human serum albumin (HSA) was characterized by examining the change in HSA fluorescence. The quenching rate constants and binding constants were calculated in the absence and presence of the denaturant. The results point to a static quenching mechanism operating in the complexes. However, the binding ability of sinomenine to denatured HSA is weaker than that of sinomenine to native HSA. Denaturation of HSA in the presence of urea is almost complete at [urea]≥ 8.0M. Upon unfolding, two fluorescence peaks were observed. One peak was assigned to the fluorescence of Trp-214 residue in a polar environment, and the other peak was assigned to the fluorescence of tyrosine residues. Compared to the free HSA, the HSA-sinomenine complex is more stable in the presence of urea.
在 pH 值为 7.40 时的水溶液中，研究了盐酸青藤碱与人血清白蛋白（HSA）在有无脲存在下的结合情况，运用荧光和三维（3D）荧光进行了研究。通过考察 HSA 荧光的变化，对人血清白蛋白（HSA）亚域 IIA 结合位点进行了特征描述。在有无变性剂的情况下计算了猝灭速率常数和结合常数。结果表明，该复合物中存在静态猝灭机制。然而，盐酸青藤碱与变性 HSA 的结合能力弱于与天然 HSA 的结合能力。在 [脲]≥8.0M 时，脲存在下 HSA 的变性几乎是完全的。展开后，观察到两个荧光峰。一个峰被分配给位于极性环境中的色氨酸-214 残基的荧光，另一个峰被分配给酪氨酸残基的荧光。与游离 HSA 相比，在脲存在下，HSA-盐酸青藤碱复合物更稳定。
