Versatility and Specificity of Flavin-Based Oxidoreductases in the Electron Transfer Reactions

Oxidoreductases are a large class of enzymes involved in the catalysis of oxidation/reduction reactions. These oxygen-utilizing biomolecules firmly control the reactions involving molecular oxygen mostly by regulating their cofactors. Flavoenzymes, a large group of oxidoreductases, possess either a flavin mononucleotide or a flavin adenine dinucleotide cofactor non-covalently bound to the protein substrate. Flavin cofactors are versatile due to reactivity and many oxidizing states allowing them to undergo electron transfer reactions. As a result, flavoenzymes can participate in a wide range of biochemical and photochemical processes including electron transport, C-H oxidations, oxidative protein folding, and even repair of cross-linked DNA. Structural studies have shown that the large variety of functions that flavoenzymes possess are limited and dependent on structure and protein folding to ensure the specific electrostatic environment. The present work concerns the structural aspects of specific flavin-dependent oxidoreductases influencing electron transfer reactions.