Porcine chymotrypsin A-pi, a more acidic chymotrypsin.
A kinetic study of procine chymotrypsin A-pi revealed two characteristic properties of this type of chymotrypsin: 1. Porcine chymotrypsin A-pi, like bovine chymotrypsin B-pi does not bind proflavin, which is a competitive inhibitor of bovine trypsin and chymotrypsin A-alpha. 2. The pH profiles of the steady-state parameters show the two usual important pK's. The basic one, pK2 = 9.6, affects both Km and kcat/Km and probably controls the binding conformation of chymotrypsin. The acidic one, pK1 = 5.7, affects kcat and kcat/Km and plays a role in the catalytic process. The value of pK1 is unusually low.
D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism*; D005415:Flavins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011485:Protein Binding; D013552:Swine; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D005415:Flavins; D014443:Tyrosine; D002918:Chymotrypsin