The lysyl 5S-hydroxylase, JMJD6 acts on proteins involved in RNA splicing. We find that in the
absence of substrate JMJD6 catalyses turnover of 2OG to succinate. 1H-NMR analyses demonstrate
that consumption of 2OG is coupled to succinate formation. MS analyses reveal that JMJD6 undergoes
self-hydroxylation in the presence of Fe(II) and 2OG resulting in production of 5S-hydroxylysine
residues. JMJD6 in human cells is also found to be hydroxylated. Self-hydroxylation of JMJD6 may
play a regulatory role in modulating the hydroxylation status of proteins involved in RNA splicing.