[Comparative study of active site structure in bovine and Pacific salmon trypsins]

The kinetic investigation was carried out on the inhibition of hydrolysis of N, alpha-benzoyl-D, L-arginine-p-nitroanilide (BApNA) for bovine and salmon trypsin by phenylmethanesulphonyl fluoride (PMSF), N, alpha-tosyl-L-lysine chloromethyl ketone (N-TLCK), N, alpha-tosyl-L-phenylalanine chloromethyl ketone (N-TPCK). Kinetic parameters of inhibition (Ki, k2) by PMSF for salmon and bovine trypsin differ insignificantly. The k2/Ki value of N-TPCK for salmon trypsin is 10 times more than of bovine trypsin. Kinetic parameters of inhibition by N-TLCK had the less difference. The Ki value of this inhibitor for salmon trypsin is 5 times less than that of bovine trypsin and k2 value is 1.7 times less.