Edwards Ana Maria
Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, 6094411, Chile,
Methods Mol Biol. 2014;1146:3-13. doi: 10.1007/978-1-4939-0452-5_1.
Flavins are a family of yellow-colored compounds with the basic structure of 7,8-dimethyl-10-alkylisoalloxazine. Riboflavin, commonly known as vitamin B2, is an essential component of living organisms and is the precursor of all biologically important flavins. In this chapter, the redox properties of flavins are described, with special emphasis in their ability to participate in both one-electron and two-electron transfer processes; hence, flavins are indispensable mediators between two-electron and one-electron processes in biological systems. The photophysical and photochemical properties of flavins are also discussed. All oxidized flavins exhibit strong absorption in the ultraviolet and visible regions and an intense yellow-green fluorescence (in their neutral oxidized form). Flavins are thermostable compounds; however, they are photosensitive. In the absence of an external reductant, the isoalloxazine ring system undergoes intramolecular photoreduction. Some flavins are efficient photosensitizers; they can induce photomodifications of compounds that are not directly modified by visible light.
黄素是一类具有7,8 - 二甲基 - 10 - 烷基异咯嗪基本结构的黄色化合物。核黄素，通常称为维生素B2，是生物体的重要组成部分，也是所有具有生物学重要性的黄素的前体。在本章中，将描述黄素的氧化还原性质，特别强调它们参与单电子和双电子转移过程的能力；因此，黄素是生物系统中双电子和单电子过程之间不可或缺的介质。还将讨论黄素的光物理和光化学性质。所有氧化型黄素在紫外和可见光区域都有强烈吸收，并呈现强烈的黄绿色荧光（处于中性氧化形式时）。黄素是热稳定化合物；然而，它们对光敏感。在没有外部还原剂的情况下，异咯嗪环系统会发生分子内光还原。一些黄素是有效的光敏剂；它们可以诱导那些不能被可见光直接修饰的化合物发生光修饰。
