Histone demethylases function through catalytic mechanisms that involve the oxidation of methyl groups on histone proteins. There are mainly two classes of histone demethylases: the amine oxidase (AO) family and the Jumonji C (JmjC) domain-containing family. The AO family, exemplified by [LSD1](href), uses flavin adenine dinucleotide (FAD) as a cofactor to oxidize methyl groups. On the other hand, the JmjC family requires [Fe(II)](href) and [α-ketoglutarate](href) as cofactors to catalyze the demethylation process.
