Daminozide 19 is selective for KDM2A. Tricarboxylic acid cycle intermediates succinate 1 and fumarate 2 were generally poor demethylase inhibitors, though KDM4E was an exception to this trend. (R)- and (S)-2-hydroxyglutarate enantiomers, produced by gain-of-function mutations to isocitrate dehydrogenase were inhibitors of the KDM2, KDM3 and KDM4 histone demethylases. The catechols 16 and 17, bipyridyl 18 and 8-hydroxyquinoline 21 inhibited all demethylases screened. By contrast, 5 most potently inhibited PHD2 (prolyl hydroxylase domain enzyme isoform 2). Each compound was screened in an AlphaScreen assay and is represented as % inhibition of the enzyme at 20 μM compound. Details of the assays are in the .