Deactivation theory

Abstract

A general model of enzyme deactivations involving unimolecular processes is introduced. For most mechanisms of this type, the parameters of the general model can be expressed in terms of actual physical parameters. The number of physical parameters that can be determined from the deactivation data cannot exceed the number of independent constants in the general model. When there is an excess of physical parameters, then some parameters must be determined from independent methods of analysis. If this is not possible, then some parameters must be left as lumped parameters or global parameters. The general form of the model can be useful in determining the number of independent, potentially active forms of the enzyme present during deactivation. Some exceptions to the general model are due to higher-order processes such as dissociation, autolysis, and biological contamination.

High‐activity enzyme‐polyurethane coatings

“…Another kinetic model assuming the existence of two dierent forms of DFPase in ECCs with dierent deactivation pathways and requiring only four physical parameters did not adequately describe the experimental data. Further, more complex mechanisms were not considered as they involved ®ve or more parameters (Henley et al, 1985). .…”

“…No signi®cant change in the activity of the highly stable form of the DFPase-ECC was observed over 350 min. The biphasic deactivation kinetics of the ECC can be modeled by a four-parameter model (Henley et al, 1985), which assumes the following scheme:…”

Hydrolysis of Lactose from Cheese Whey Using a Reactor with β-Galactosidase Enzyme Immobilised on a Commercial UF Membrane

“…lactose and whey, respectively. (Henley and Sadana, 1986). At the same time, the glucose concentration decreases with time.…”

“…If the molecule would get a lot of kinetic energy, those bonds could be broken producing the denaturalisation and the consequent loss of catalytic activity (Sadana, 1991;Henley and Sadana, 1986).…”

Development characterization and use of a high‐performance enzymatic time‐temperature integrator for the control of sterilization process' impacts

“…The first one assumes that multiphasic inactivation curves result from a continuous spectrum of enzyme molecules with different free inactivation enthalpies (Kawamura et al, 1981). The second one assumes a stepwise loss of activity in only one population of immobilized enzymes (Henley and Sadana, 1986). These two hypothesis, however, have been observed as being not suitable to explain biphasic behavior of a-amylases and chymotrypsin when the latter are immobilized (UlbrichHofmann et al, 1993).…”