Flavins

Flavin is the common name for a group of organic compounds based on pteridine, formed by the tricyclic heterocycle isoalloxazine. The riboflavin (RF), vitamin B2, is an essential precursor of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) co-enzymes. Another compound of the flavin family is lumiflavin. The flavins have in common the isoalloxazine ring system where the redox process occurs. The nature of the group attached to the N-10, is the flavin members differentiation and can influence the flavin adsorption orientation on the electrode surface, leaving the active site more or less available. The redox process of the flavins is thermodynamically reversible, irrespective of whether one or two electrons per flavin molecule are being transferred, which means that their redox states (quinone state, semiquinone state, hydroquinone state) must be considered.