Acetylation is a chemical process where an acetyl group (–COCH₃) is added to a molecule, often a protein or a carbohydrate. This modification can influence the function and activity of the molecule, affecting processes like gene expression and metabolism. Acetylation is crucial in various biological systems, including the regulation of enzymes and the structure of histones in DNA. In the context of biochemistry, acetylation can alter the interaction between proteins and DNA, impacting how genes are expressed. This process is reversible, meaning that the acetyl group can be removed, allowing for dynamic regulation of cellular functions. Understanding acetylation is important in fields like pharmacology and molecular biology.