US Patent 7670795 Methods for assaying acetyl transferase or deacetylase activity

The invention provides methods and kits for characterizing the activity of an acetyl transferase or deacetylase. The method involves enzymatically acetylating or deacetylating in vitro a substrate that is a peptide fragment of a full-length polypeptide, and then non-enzymatically acylating the peptide substrate with acyl groups that differ in molecular weight from the enzymatically added or removed acetyl groups. Typically, deuterated acetic anhydride is used to non-enzymatically acylate the substrate. The fully acylated substrate is then characterized by mass spectrometry to determine the amino acid positions of the substrate that are enzymatically acetylated or deacetylated.