Chymotrypsin, Human Pancreas

Chymotrypsin preferentially catalyzes the hydrolysis of peptide bonds involving L-isomers of tyrosine, phenylalanine and tryptophan. It also readily acts upon amides and esters of susceptible amino acids. Chymotrypsin catalyzes the hydrolysis of bonds of leucyl, methionyl, asparaginyl and glutamyl residues. Chymotrypsinogen A is extracted from pancreatic tissue as a zymogen. Pancreatic extract contains approximately equal amounts of two forms of the zymogen, chymotrypsin A and chymotrypsin B. Chymotrypsin A may be activated to alpha, pi, beta, or gamma chymotrypsin. The enzyme is inhibited by heavy metals, the natural trypsin inhibitors to various degrees, an inhibitor from potato, and organophosphorous compounds. I.U.B.: 3.4.21.1 Applications: Suitable for antigenic applications in immunological protocols. Shows no trypsin activity when assayed against N-benzyl-L-arginine-p-nitroanilide. Other applications have not been tested. Rcommended Dilutions: Optimal dilutions to be determined by the researcher. Extinction coefficient: 20.4 Specificity: In addition to bonds involving aromatic amino acids, chymotrypsin catalyzes at a high rate the hydrolysis of bonds of leucyl, methionyl, asparaginyl, and glutamyl residues. A recent study has been made by Berezin and Martinek (1970) and Baumann et al. (1970). Inhibitors: The enzyme is inhibited by heavy metals, the natural trypsin inhibitors to various degrees ( Birk 1961), an inhibitor from potato ( Ryan and Balls 1962), and organophosphorus compounds. Gel filtration of chymotrypsin removes autolysis products and other contaminants ( Yapel et al. 1966). The specificity of a-chloroketone as [[alpha]]-chymotrypsin inhibitor has been studied by Kumar and Hein (1970). Erlanger et al. (1970) report phenothiazine-N-carbonyl chloride to be specific for chymotrypsin inhibition. Storage and Stability: Lyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.