Rko. Apenten et N. Berthalon, DETERMINATION OF ENZYME GLOBAL THERMOSTABILITY FROM EQUILIBRIUM AND KINETIC-ANALYSIS OF HEAT INACTIVATION, Food chemistry, 51(1), 1994, pp. 15-20
An equilibrium-kinetic description for the two-stage irreversible ther
moinactivation of enzymes (N double left right arrow D double right ar
row I) is examined by using chymotrypsin as a model. The parameter Del
ta G for enzyme unfolding (N double left right arrow D) and activation
free energy for the D double right arrow I reaction (Delta G(i)(#)) w
ere summed to provide an index of enzyme global thermostability (Delta
G(#); Delta G(#) = Delta G + Delta G(i)(#)). There was good agreement
between calculated and experimental global thermostability (i.e. enzy
me stability with respect to reversible and irreversible thermoinactiv
ation reaction steps) at 0-60 degrees C. The results indicate that enz
yme global thermostability may be markedly dependent on the rate of en
zyme folding.