Tikhonova Tatiana N, Shirshin Evgeny A, Budylin Gleb S, Fadeev Victor V, Petrova Galina P
International Laser Center and ‡Department of Physics, M.V. Lomonosov Moscow State University , Moscow 119991, Russia.
J Phys Chem B. 2014 Jun 19;118(24):6626-33. doi: 10.1021/jp501277z. Epub 2014 Jun 10.
Intrinsic fluorescence quenching of bovine serum albumin (BSA) and europium(III) luminescence in BSA complexes were investigated. The number of BSA binding sites (n) and equilibrium constant (Keq) values were determined from both measurements provided qualitatively different results. While the modified Stern-Volmer relation for BSA fluorescence quenching gave n = 1 at pH 4.5 and pH 6, two sets of binding sites were determined from Eu(3+) luminescence with n1 = 2, n2 = 4 at pH 6 and n1 = 1, n2 = 2 at pH 4.5. The model explaining the discrepancy between the results obtained by these fluorescent approaches was suggested, and the limitations in application of the "log-log" Stern-Volmer plots in analysis of binding processes were discussed.
研究了牛血清白蛋白（BSA）的固有荧光猝灭以及BSA配合物中铕（III）的发光。通过两种测量方法确定了BSA结合位点的数量（n）和平衡常数（Keq）值，结果在定性上有所不同。虽然用于BSA荧光猝灭的修正Stern-Volmer关系在pH 4.5和pH 6时给出n = 1，但从Eu(3+)发光确定了两组结合位点，在pH 6时n1 = 2，n2 = 4，在pH 4.5时n1 = 1，n2 = 2。提出了解释这些荧光方法所得结果差异的模型，并讨论了“对数-对数”Stern-Volmer图在结合过程分析中的应用局限性。
