Coenzyme F420 a coenzyme involved in redox reactions in methanogens, in many Actinobacteria, and sporadically in other bacterial lineages. It is a flavin derivative. The coenzyme is a substrate for coenzyme F420 hydrogenase, 5,10-methylenetetrahydromethanopterin reductase and methylenetetrahydromethanopterin dehydrogenase. A particularly rich natural source of F420 is Mycobacterium smegmatis, in which several dozen enzymes use F420 instead of the related cofactor FMN used by homologous enzymes in most other species. Function of coenzyme F420-dependent NADP reductase in methanogenic archaea containing an NADP-dependent alcohol dehydrogenase.Methanogenic archaea growing on ethanol or isopropanol as the electron donor for CO2 reduction to CH4 contain either an NADP-dependent or a coenzyme F420-dependent alcohol dehydrogenase.