title: Enzymatic characterization of anionic trypsin of the catfish (Parasilurus asotus).
abstract: An anionic trypsin, isolated from the pancreatic extract of the catfish (Parasilurus asotus), had a pH optimum of 8.3 for the hydrolysis of N-tosyl-L-arginine methyl ester. The enzyme was most stable at pH 6.0-8.5, and was stabilized by calcium ions. The enzyme was inhibited by typical trypsin inhibitors including some serine proteinase inhibitors. Km and kcat values of the enzyme for N-tosyl-L-arginine methyl ester and N-tosyl-L-lysine methyl ester were quite similar to those of bovine cationic trypsin.
mesh_terms: D000818:Animals; D000838:Anions; D001665:Binding Sites; D002118:Calcium / Q000502:physiology; D005399:Fishes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D013379:Substrate Specificity; D013696:Temperature; D014357:Trypsin / Q000032:analysis*; D014361:Trypsin Inhibitors / Q000494:pharmacology
chemical_list: D000838:Anions; D014361:Trypsin Inhibitors; D014357:Trypsin; D002118:Calcium