   3.4.22.37 | bovine pancreatic secretory trypsin inhibitor |
i.e. PSTI bovine, about 33% inhibition at 0.0005 mM, 66% at 0.001 mM, and 87% at 0.0025 mM, a Kazal-type serine proteinase inhibitor purified from pancreas, bovine pancreatic secretory trypsin inhibitor having an essential Arg residue at the P1 position of the reactive site, and containing Tyr and Asn residues the P2' and P3' sites, specifically inhibits the activity of the Arg-specific gingipain R, whereas porcine inhibitor, possessing a Lys residue at the P1 position, exhibits activity only against the Lys-specific cysteine proteinase gingipain K, EC 3.4.22.47. The inhibitory effect is eliminated by Arg residue modification in 0.2 M borate buffer, pH 9.0, and 50 mM excess of cyclohexanedione in a 1 : 30 molar ratio at 37°C. The association equilibrium constant is 0.0016 mM |
 |
