Histone acetyltransferases (HATs) are enzymes that are required for the complete activation of various genes. Their role is to acetylate the lysine amino acids in the histone molecules by transferring an acetyl group from acetyl-CoA to form ε-N-acetyllysine.This process normally happens after translation of the histones. As DNA is wrapped around histones, acetylation of the histones modify the genes and can therfore upregulate or downregulate the gene expression. This process is readily reversible by histone deacetylases. Therefore the acetylation state of histones is highly dynamic.