Tubastatin A Hydrochloride (Tubastatin A HCl) is a potent and selective HDAC6 inhibitor with IC50 of 15 nM in a cell-free assay, and is selective (1000-fold more) against all other isozymes except HDAC8 (57-fold more). Tubastatin A Hydrochloride also inhibits HDAC10 and metallo-β-lactamase domain-containing protein 2 (MBLAC2).