Chymotrypsin is a highly-purified serine endopeptidase derived from bovine pancreas that preferentially hydrolyzes at the carboxyl side of aromatic amino acids: Tyr, Phe and Trp. Cleavage may also be observed, but at a lower rate, at Leu and Met. Chymotrypsin activity is optimal in the pH range of 7.0–9.0. This sequencing grade enzyme can be used alone or in combination with other proteases to produce protein digests for peptide mapping applications or protein identification by peptide mass fingerprinting or MS/MS spectral matching. It is suitable for digestion reactions in-solution or in-gel.