Coenzyme F420 is a family of coenzymes involved in redox reactions in a number of bacteria and archaea. It is derived from coenzyme FO (7,8-didemethyl-8-hydroxy-5-deazariboflavin) and differs by having a oligoglutamyl tail attached via a 2-phospho-L-lactate bridge. F420 is so named because it is a flavin derivative with an absorption maximum at 420 nm.
F420 is structurally similar to FMN, but catalytically it is similar to NAD and NADP: it has low redox potential and always transfer a hydride. As a result, it is not only a versatile cofactor in biochemical reactions, but also being eyed for potential as an industrial catalyst. Similar to FMN, it has two states: one reduced state, notated as F420-H2, and one oxidized state, written as just F420.[5] FO has largely similar redox properties, but cannot carry an electric charge and as a result probably slowly leaks out of the cellular membrane.[3]
A number of F420 molecules, differing by the length of the oligoglutamyl tail, are possible; F420-2, for example, refers to the version with two glutamyl units attached. Lengths from 4 to 9 are typical.[3]