Tubastatin A is a potent and selective HDAC6 inhibitor. Tubastatin A is a potent HDAC6 inhibitor with an IC50 value of 15 nM. Comparatively, it demonstrates over 1,000-fold selectivity against all other HDAC isoforms (IC50 >16 ?M), excluding HDAC8 (IC50= 0.9 ?M). Tubastatin A induces ?-tubulin hyperacetylation at 2.5 ?M in primary cortical neuron cultures. In a model of oxidative stress induced by glutathione depletion, tubastatin A displays dose-dependent neuronal protection of primary cortical neuron cultures at 5-10 ?M.