Figure 2. The role of ascorbate in histone demethylation.

As a cofactor for Jmjc domain-containing histone demethylases (JmjC), ascorbate participates in the oxidation of tri-methylated, di-methylated and mono-methylated lysine in histones, which is followed by a spontaneous removal of the hydroxymethyl group. The methylation of an unmodified lysine in histones could be reestablished by HMT, thus complete a cycle of histone methylation–demethylation.