Conformation and Activity of Chymotrypsin: The p H-Dependent, Substrate-Induced Proton Uptake

Abstract
Hydrogen ion uptake by chymotrypsin during reversible binding of specific substrate is shown to be due to an ionizing group of the enzyme with a pK(apparent) ∼9 in the free enzyme. This pK(apparent) is shifted to higher value in the enzyme-substrate complexes. Previous results indicating an equilibrium, controlled by this ionizing group, between active and inactive conformational forms of chymotrypsin are confirmed.
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