Abstract

The distinctive features of firefly luciferase bioluminescence are complex changes in the shape of the spectra and λ_max of bioluminescence with varying pH, temperature, and enzyme structure. An analysis of the published data and the authors’ own results leads to the conclusion that the keto–enol tautomerism of the oxyluciferin molecule explains the observed complex spectral changes most reliably. Only one molecule of an electronically excited product is formed in the active center of the enzyme; therefore, the emitter can be considered as an intramolecular probe characterizing the properties of the emitter microenvironment in the active center of the enzyme. The superposition of two or three forms of the emitter, recorded in the bioluminescence spectra, indicates the coexistence of various conformational forms of luciferase, being in dynamic equilibrium in the reaction medium. An analysis of the bioluminescence spectra enables the identification of qualitatively and quantitatively different conformers of the enzyme and their change with varying external conditions and luciferase structure.

中文翻译：

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发射体作为萤光素酶活性中心的分子内探针

摘要

萤火虫萤光素酶的生物发光的显着特征是在光谱和λ的形状复杂的变化_最大pH，温度和酶结构变化引起的生物发光现象。对已发表的数据和作者的研究结果进行的分析得出的结论是，氧荧光素分子的酮-烯醇互变异构现象最可靠地解释了所观察到的复杂光谱变化。在酶的活性中心仅形成一个分子的电子激发产物。因此，发射极可以被认为是表征酶活性中心中发射极微环境特性的分子内探针。在生物发光光谱中记录的两种或三种形式的发射体的叠加表明荧光素酶各种构象形式的共存，在反应介质中处于动态平衡。