Histone deacetylase class I and II enzyme (HDAC (class I and II))

Histone deacetylase class I and II enzymes are a family of zinc-dependent enzymes that remove acetyl groups from lysine residues on histones as well as non-histone proteins. This action increases the positive charge on histones, promoting tighter DNA binding and resulting in chromatin condensation that represses gene transcription. These enzymes play a central role in epigenetic regulation by controlling the balance between active (hyperacetylated) and silent (hypoacetylated) chromatin states. Beyond their canonical function in modifying histones, they also regulate the stability and function of various non-histone proteins involved in cell signaling pathways. Dysregulation or aberrant activity/expression of these enzymes is implicated in cancer development/progression, neuropsychiatric disorders such as schizophrenia, inflammation-related diseases, among others. Several drugs targeting these enzymes—known as histone deacetylase inhibitors—are used therapeutically for cancer treatment by reactivating silenced tumor suppressor genes through epigenetic modulation.

Other names

HDACsHistone deacetylase enzymesClass I HDAC (e.g., HDAC1, HDAC2, HDAC3, HDAC8)Class II HDAC (e.g., HDAC4, HDAC5, HDAC6, HDAC7, etc.)

Inhibition of deacetylase activity leading to increased acetylation of histones and non-histone proteins; results in chromatin relaxation and reactivation of silenced genes such as tumor suppressors or pro-apoptotic factors.