The superfamily of GNC5 related N-acetyltransferases, also referred to as the GNATsuperfamily, is the superfamily of acetyltransferases that contains the histone acetyltransferases (HATs). Histone acetyltranferase (HAT) enzymes are the catalytic subunit of large multisubunit HAT complexes that acetylate the epsilon-amino group of specific lysine residues on histone tails to promote transcriptional activation (PMID:11437231).