Notes: A robust ELISA-based histone deacetylase (HDAC) activity assay was developed for use with mammalian cells. The assay was then shown effective in screening selective HDAC inhibitors. Mammalian cell-derived HDAC isoforms, instead of recombinant proteins, was a key feature of this ELISA, developed using the HDAC-Glo™ Class IIa Assay (Cat.# G9560) and HDAC-Glo™ 2 Assay (Cat.# G9590). (4634)