Carrero J, Jameson D M, Gratton E
Department of Physics, University of Illinois at Urbana-Champaign 61801-3080, USA.
Biophys Chem. 1995 Apr;54(2):143-54. doi: 10.1016/0301-4622(94)00133-5.
Oxygen quenching experiments were carried out on zincprotoporphyrin IX reconstituted myoglobin (MbFe-->Zn) at different temperatures and two solvent viscosities. The data were fit to a dynamic model for quenching of fluorophores in protein interiors previously presented (Biophysical J., 45 (1984) 789-794). The parameters associated with the oxygen entry rate (k+), exit rate (k-), and migration rate (chi) in the protein were obtained at six temperatures and two viscosities (1 and 8 cp), along with the activation enthalpies associated with the above rates (k+ and k-). The partition coefficient (alpha) was calculated at each temperature along with the free energy, delta G0, associated with this partition. The rate parameters (k+, k-, chi) and the partition coefficient (alpha) have also been determined for the sample in 40% sucrose (8 cp), to evaluate the effect of bulk solvent viscosities on these values. The steady-state Stern-Volmer quenching plot was calculated using the rate parameters obtained from the analysis (of the dynamic model). Comparison of the Stern-Volmer points obtained using the dynamic model and those obtained experimentally showed excellent agreement.
在不同温度和两种溶剂粘度条件下，对锌原卟啉IX重构肌红蛋白（MbFe→Zn）进行了氧猝灭实验。数据拟合至先前提出的蛋白质内部荧光团猝灭动力学模型（《生物物理杂志》，45 (1984) 789 - 794）。在六个温度和两种粘度（1和8厘泊）条件下，获得了与蛋白质中氧进入速率（k+）、退出速率（k-）和迁移速率（χ）相关的参数，以及与上述速率（k+和k-）相关的活化焓。计算了每个温度下的分配系数（α）以及与此分配相关的自由能ΔG0。还测定了40%蔗糖（8厘泊）溶液中样品的速率参数（k+、k-、χ）和分配系数（α），以评估主体溶剂粘度对这些值的影响。使用从动力学模型分析中获得的速率参数计算稳态斯特恩 - 沃尔默猝灭图。比较使用动力学模型获得的斯特恩 - 沃尔默点与实验获得的点，结果显示出极好的一致性。
