Complex sentence: Histone acetyltransferase (HAT) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to lysine to form ε-N-acetyl lysine.
Split into simpler sentences: Histone acetyltransferase (HAt) is an enzyme that acetylates conserved lysine amino acids on histone proteins. It does this by transferring an acetyl group from acetyl CoA to lysine to form ε-N-acetyl lysine.