May be a histone demethylase that specifically demethylates 'Lys-36' of histone H3, thereby playing a central role in histone code (By similarity). Represses transcriptional silencing by negatively affecting heterochromatin stability. 2 2-oxoglutarate + N(6),N(6)-dimethyl-L-lysyl(36)-[histone H3] + 2 O2 = 2 CO2 + 2 formaldehyde + L-lysyl(36)-[histone H3] + 2 succinate Binds 1 Fe(2+) ion per subunit. The JmjC domain mediates the demethylation activity. Belongs to the JHDM1 histone demethylase family. In contrast to other JHDM1 histone demethylases, it lacks the iron catalytic His in position 370 which is replaced by a Tyr residue and has no histone demethylase activity in vitro (PubMed:16362057). It therefore may not be functional in vivo.