Nernst-Michaelis-Menten framework unlocks electrochemical kinetics for laccases

Determining oxidoreductase kinetic parameters remains challenging due to spectrophotometric method limitations. Here, we present an innovative approach combining electrochemistry and enzymology principles through a novel Nernst-Michaelis-Menten theoretical framework. This model merges the Nernst equation, describing electrochemical equilibrium, with Michaelis-Menten kinetics, enabling accurate enzyme parameters determination, via chronopotentiometry. Using a commercial laccase from Trametes versicolor as a model system, we demonstrate precise kinetic parameters measurement for both chromophoric (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) - ABTS, K_m = (56.7 ± 6.3) μM) and non-chromophoric (hydroquinone, K_m = (196 ± 59) μM) substrates, validated against established techniques. The method requires minimal enzyme quantities and enables rapid analysis. This approach overcomes current methodological limitations and extends to other oxidoreductases, providing a powerful tool for enzyme characterization. Our work provides a new paradigm for enzyme kinetics, expanding the scope of analysable enzymatic systems, including those that were previously challenging to characterize with conventional methods.