Abstract
Histone N-epsilon-methyl lysine demethylases are important in epigenetic regulation. KDM4E (histone lysine demethylase 4E) is a representative member of the large Fe(II)/2-oxoglutarate-dependent family of human histone demethylases. In the present study we report kinetic studies on the reaction of KDM4E with O-2. Steady-state assays showed that KDM4E has a graded response to O-2 over a physiologically relevant range of O-2 concentrations. Pre-steady state assays implied that KDM4E reacts slowly with O-2 and that there are variations in the reaction kinetics which are dependent on the methylation status of the substrate. The results demonstrate the potential for histone demethylase activity to be regulated by oxygen availability.