Histone demethylase that specifically demethylates 'Lys-9' of histone H3, thereby playing a role in histone code. Does not demethylate histone H3 'Lys-4', H3 'Lys-27', H3 'Lys-36' nor H4 'Lys-20'. Only able to demethylate trimethylated H3 'Lys-9', with a weaker activity than KDM4A, KDM4C and KDM4D. Demethylation of Lys residue generates formaldehyde and succinate.,KDM4B,JMJD2B,TDRD14B,Epigenetics & Nuclear Signaling,Chromatin Modifying Enzymes,Demethylation,DNA Damage & Repair,Nuclear Receptor Signaling,Signal Transduction,Kinase,Serine/threonine kinases,Cell Biology & Developmental Biology,Cell Cycle,Immunology & Inflammation,KDM4B