作者:Richard B. Thompson、Badri P. Maliwal、Carol A. Fierke
DOI:10.1021/ac971199+
日期:1998.5.1
We demonstrate that by use of a biosensor approach employing wild type human apocarbonic anhydrase II and a newly synthesized fluorescent ligand, ABD-M, free Zn(II) may be determined in solution at concentrations in the picomolar range with good accuracy by fluorescence anisotropy. Fluorescence anisotropy enjoys the same freedom from artifact as wavelength ratiometric approaches widely used for determining metal ions in solution such as Ca(II). In addition, we demonstrate that anisotropy-based determinations exhibit an important advantage, a broad dynamic range, which has not been demonstrated for wavelength ratiometric approaches. In particular, by judicious choice of excitation and emission wavelengths, the concentration range over which Zn(II) may be determined accurately can be increased by approximately 2 orders of magnitude. As ABD-M also exhibits significant changes in excitation and emission spectra as well as lifetime upon binding to the active-site Zn(II) in holocarbonic anhydrase, it should also be useful for wavelength ratiometric and lifetime-based determinations.
我们证明,通过使用野生型人类无碳酸酐酶 II 和新合成的荧光配体 ABD-M 的生物传感器方法,可以利用荧光各向异性准确测定溶液中浓度在皮摩尔范围内的游离锌(II)。与广泛用于测定溶液中金属离子(如 Ca(II))的波长比率法相比,荧光各向异性法同样不受人为因素的影响。此外,我们还证明了基于各向异性的测定方法具有一个重要优势,即动态范围广,而这是波长比测法所不具备的。特别是,通过明智地选择激发和发射波长,可准确测定锌(II)的浓度范围可增加约 2 个数量级。由于 ABD-M 在与全碳酸酐酶活性位点 Zn(II)结合后,其激发和发射光谱以及寿命也会发生显著变化,因此也可用于基于波长比率和寿命的测定。