Not available outside of the UK & Ireland.

Analysis Note

Protein determined by E1%/280

Minimum 85% protein

Application

The product has been used to investigate the inhibitory effect of several ether oligomers against the enzyme. It has also been used to cleave pro-phenoloxidase in order to estimate total phenoloxidase in haemolymph. Furthermore, the enzyme has been used as a positive control in chymotrypsin assays using salivary gland and anterior midgut extracts of Deraeocoris nigritulus.

α-Chymotrypsin from bovine pancreas has been used in a study to investigate protein extraction by Winsor-III microemulsion systems. α-Chymotrypsin from bovine pancreas has also been used in a study to investigate a new specific fullerene-based fluorescent probe for trypsin.

Biochem/physiol Actions

α-Chymotrypsin is a serine peptidase and has 241 amino acid residues contained in three polypeptide chains (A chain-13 residues, B chain-131 residues, and C chain-97 residues) linked by disulfide bridges. Molecular weight of this enzyme is found to be 25 kDa. The pI is 8.75. It selectively hydrolyzes peptide bonds on the C-terminal side of tyrosine, phenylalanine, tryptophan, and leucine. Ca²⁺ activates and stabilizes the enzyme. The enzyme is inhibited by diisopropyl fluorophosphate (DFP), phenylmethanesulfonyl fluoride (PMSF), N-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK), chymostatin, aprotinin, α1-antitrypsin, and α2-macroglobulin, as well as 10 mM of Cu²⁺ and Hg²⁺.

A serine protease that hydrolyzes peptide bonds with aromatic or large hydrophobic side chains (Tyr, Trp, Phe, Met, Leu) on the carboxyl end of the bond.

Other Notes

View more information on chymotrypsin at www.sigma-aldrich.com/enzymeexplorer

Packaging

5, 25, 100 mg in glass bottle

Preparation Note

The powder may be reconstituted in 1 mM HCl at 2 mg/mL concentration to form a clear solution.

Prepared free of autolysis products and low molecular weight contaminants.

Unit Definition

One unit will hydrolyze 1.0 µmole of BTEE per min at pH 7.8 at 25 °C.