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Updated: Jun 25, 2026

Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions
Published on: April 4, 2014
Catalytic effectiveness, a measure of enzyme proficiency for industrial applications
Richard J Fox1, Michael D Clay
1Codexis, Inc., 200 Penobscot Drive, Redwood City, CA 94063, USA. richard.fox@codexis.com
Abstract:
Recent attention has been paid to the inadequacy of using the ratio Vmax/KM as a measure of enzyme performance, particularly in the context of industrial biocatalysis. This can lead to misleading expectations of enzyme performance and can be troublesome when used to select among different variants for scale-up evaluation under process conditions. To address these issues, we derive the average velocity based on the time-integrated behavior of the enzyme over the course of the reaction. The resulting expression, deemed catalytic effectiveness, captures important features of the system that have heretofore been ignored (such as highly variable substrate and/or product concentrations and inhibition) and offers a rigorous way to compare enzymes for their capacity to carry out industrial transformations.
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