Elimination of cannibalistic denaturation by enzyme immobilization or inhibition

Abstract

The cannibalistic denaturation of α-chymotrypsin (EC 3.4.21.1) around neutral pH can be eliminated by immobilization (insolubilization) of the enzyme or by inhibition by specific reversible inhibitors, but the high-pH denaturation cannot be. The denaturation of the immobilized enzyme at high pH follows first-order kinetics, just as the denaturation of the soluble enzyme does. These results lend credence to the description of the denaturation of chymotrypsin as cannibalistic around neutrality and due to a hydroxide ion reaction at high pH; this interpretation followed from kinetic arguments given in the previous article [Wu, H.-L., Wastell, A. & Bender, M. L. (1981) Proc. Natl. Acad. Sci. USA 78, 4116-4117]. Elimination of denaturation around neutrality by immobilization may be the reason why membrane-bound enzymes are so common in vivo .