Kinetic evidence for a two-step mechanism for the binding of chymotrypsin to alpha 1-proteinase inhibitor.
We have used the proflavin displacement method and a stopped-flow apparatus to measure the rate constant for the binding of 2 microM-chymotrypsin to 20-125 microM-alpha 1-proteinase inhibitor. The observed pseudo-first-order constant showed a hyperbolic dependence on alpha 1-proteinase inhibitor concentration, suggesting a reaction mechanism in which a fast pre-equilibrium (K = 0.19 mM) is followed by a first-order formation of the final complex (k = 252 s-1).
Bruch
M
M
Laboratoire d'Enzymologie, Faculté de Pharmacie, Université Louis Pasteur de Strasbourg, France.
Bieth
J G
JG
D000209:Acute-Phase Proteins / Q000378:metabolism*; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism*; D007700:Kinetics; D011480:Protease Inhibitors / Q000378:metabolism*; D000515:alpha 1-Antitrypsin
D000209:Acute-Phase Proteins; D001798:Blood Proteins; D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D002918:Chymotrypsin