MECHANISM OF TRYPTOPHAN FLUORESCENCE QUENCHING

我们研究了时间分辨和稳态荧光 N-乙酰基-L-色胺的猝灭。(NATA)由丙烯酰胺和 在丙二醇中的一系列粘度范围内的碘化物。这个 NaTA被丙烯酰胺和碘化物猝灭导致非均质性 强度衰减随猝灭剂浓度的增加而增加。 我们将NATA的复杂衰变归因于 扩散和荧光团-猝灭剂相互作用的性质。 同时考虑频域数据和稳态数据 证明了猝灭速度指数地依赖于 荧光基团-猝灭距离，表明模型的有效性 其包括猝灭常数，该猝灭常数指数地依赖于 距离。关于猝灭的距离依赖关系的数据是 对于理解天然蛋白质的猝灭很重要。

We examined the time-resolved and steady-state fluorescence quenching of N-acetyl-L-tryptophanamide. (NATA) by acrylamide and iodide, over a range of viscosities in propylene glycol. The quenching of NATA by acrylamide and iodide results in heterogeneity of the intensity decay which increases with the quencher concentration. We attribute the complex decay of NATA to transient effects in diffusion and the nature of the fluorophore-quencher interaction. Consideration of both the frequency-domain and steady-state data demonstrate that the quenching rate depends exponentially on the fluorophore-quencher distance, indicating the validity of a model which include a quenching constant which depend exponentially on distance. Such data on the distance dependence of quenching is important for understanding quenching of native proteins.