Parul D A, Bokut S B, Milyutin A A, Petrov E P, Nemkovich N A, Sobchuk A N, Dzhagarov B M
A.D. Sakharov International Environmental University, Minsk, Belarus.
J Photochem Photobiol B. 2000 Nov;58(2-3):156-62. doi: 10.1016/s1011-1344(00)00122-6.
Time-resolved fluorescence of 1,8-anilinonaphthalene sulfonate (1,8-ANS) fluorescent probe bound to intact human oxyhemoglobin (HbO2) is investigated. Fluorescence emission spectra of 1,8-ANS in a potassium buffer solution (pH 7.4) of HbO2 undergo a substantial blue shift during first 6 ns after pulsed optical excitation at 337.1 nm. Nonexponential fluorescence kinetics of 1,8-ANS in the HbO2 solution are studied by the decay time distribution and conventional multiexponential analyses for a set of emission wavelength range of lambdaem = 455-600 nm. These fluorescence decays contain components with mean decay times of <0.5 ns, 3.1-5.5 ns, and 12.4-15.1 ns with spectrally-dependent relative contributions. The shortest decay component is assigned to free 1,8-ANS molecules in the bulk buffer environment, whereas the two longer decay components are assigned to two types of binding sites of 1,8-ANS in the HbO2 molecule presumably differing by polarity and accessibility to water molecules. The results represent the first experimental evidence of heterogeneous binding of 1,8-ANS to intact human oxyhemoglobin.
研究了与完整的人氧合血红蛋白（HbO2）结合的1,8-苯胺基萘磺酸盐（1,8-ANS）荧光探针的时间分辨荧光。在337.1nm脉冲光激发后的前6ns内，HbO2的钾缓冲溶液（pH 7.4）中1,8-ANS的荧光发射光谱发生了显著的蓝移。通过衰减时间分布和传统的多指数分析，对发射波长范围为λem = 455 - 600nm的一组数据，研究了HbO2溶液中1,8-ANS的非指数荧光动力学。这些荧光衰减包含平均衰减时间分别为<0.5ns、3.1 - 5.5ns和12.4 - 15.1ns的成分，且具有光谱依赖性的相对贡献。最短的衰减成分归因于大量缓冲环境中的游离1,8-ANS分子，而两个较长的衰减成分归因于HbO2分子中1,8-ANS的两种结合位点，这两种位点可能在极性和对水分子的可及性方面有所不同。这些结果代表了1,8-ANS与完整的人氧合血红蛋白异质结合的首个实验证据。
