Systematic Theoretical Study on the pH-Dependent Absorption and Fluorescence Spectra of Flavins

Flavins are a class of organic compounds with the basic structure of 7,8-dimethy-10-alkyl isoalloxazine. They are ubiquitous in nature and participate in many biochemical reactions. Due to various existing forms, there is a lack of systematic research on the absorption and fluorescence spectra of flavins. In this study, employing the density functional theory (DFT) and time-dependent (TD) DFT, we calculated the pH-dependent absorption and fluorescence spectra of flavin of three redox states (quinone, semiquinone, and hydroquinone) in solvents. The chemical equilibrium of three redox states of flavins and the pH effect on the absorption spectra and fluorescence spectra of flavins were carefully discussed. The conclusion helps with identifying the existing forms of flavins in solvent with different pH values.

Automated summary

In this study, we used DFT and TD-DFT to calculate the pH-dependent absorption and fluorescence spectra of flavin in three redox states (quinone, semiquinone, and hydroquinone) in solvents. The chemical equilibrium of these states and the pH effect on the spectra were discussed. This conclusion helps identify the existing forms of flavin in solvents with different pH values.