Involved in melatonin degradation (PubMed:25728912). Catalyzes the hydroxylation of melatonin to produce 2-hydroxymelatonin (PubMed:25728912). 2-oxoglutarate + melatonin + O2 = 2-hydroxymelatonin + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Optimum pH is 8.0. Optimum temperature is 30 degrees Celsius. Expressed in roots and shoots. Induced by cadmium. Belongs to the iron/ascorbate-dependent oxidoreductase family. Extended N-terminus.