Histone deacetylase (Class I, II, IV) (HDAC (Class I/II/IV))

Histone deacetylases (HDACs) are a family of enzymes that catalyze the removal of acetyl groups from lysine residues on histone and non-histone proteins, resulting in chromatin condensation, transcriptional repression, and regulation of numerous non-histone proteins. HDACs are subdivided into several classes: Class I (HDAC1, 2, 3, 8), Class II (IIa: HDAC4, 5, 7, 9; IIb: HDAC6, 10), and Class IV (HDAC11). Together, these isoforms play critical roles in epigenetic regulation, cell fate determination, signal transduction, and disease pathogenesis, particularly cancer, neurodegeneration, and inflammatory disorders. Many therapeutically relevant drugs—primarily in oncology—target these classes collectively, but there is substantial research focused on developing isoform-selective inhibitors to improve safety and efficacy profiles.

Other names

Histone deacetylase (general, for all isoforms in these classes)HDACsLysine deacetylase (KDAC)EC 3.5.1.98

Inhibition of enzymatic deacetylation of lysine residues on histones and non-histone proteins, leading to chromatin relaxation and transcriptional reactivation of silenced genes. Cell cycle arrest, induction of apoptosis, and increased differentiation (anticancer mechanisms). Modulation of immune and inflammatory responses.