Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre 687 4169-007 Porto, Portugal.
Chemphyschem. 2013 Aug 26;14(12):2711-6. doi: 10.1002/cphc.201300330. Epub 2013 Jun 13.
Firefly oxyluciferin presents a pH-sensitive fluorescence in aqueous solutions. Its fluorescence spectra are composed of two green peaks at different pH values, despite the enolate anion being the only emitter. A computational approach was used to further elucidate the photoprotolytic cycle of oxyluciferin and investigate its pH sensitivity. It was found that oxyluciferin forms π-π stacking complexes both in the ground and excited states, at basic and acidic/neutral pH. However, at different pH values, these complexes adopt a different conformation, which explains the lower energy of the emission at acidic/neutral pH, in comparison with the emission at basic pH.
萤火虫荧光素在水溶液中呈现出 pH 敏感的荧光。尽管烯醇盐阴离子是唯一的发光体，但它的荧光光谱由两个不同 pH 值下的绿色峰组成。通过计算方法进一步阐明了荧光素的光解循环，并研究了其 pH 敏感性。结果发现，荧光素在碱性和酸性/中性 pH 下，在基态和激发态都形成了π-π堆积复合物。然而，在不同的 pH 值下，这些复合物采用不同的构象，这解释了在酸性/中性 pH 下的发射能量较低的原因，与碱性 pH 下的发射相比。
