<p>The present invention provides compounds and methods for assaying activities of enzymes such as histone deacetylases and histone acetyltransferases. In some embodiments, the methods may be performed in one step. The compounds described herein features peptide-based compounds having at least one blocked lysine or arginine residue which are coupled to reporter moieties. The methods described herein involve reacting a compound described herein with an enzyme, such as a histone deacetylase enzyme or a histone acetyltransferase enzyme, and an endopeptidase that recognizes basic amino acids to release the reporter moiety which may be subsequently detected.</p>