Related Experiment Video
Updated: May 14, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Insights into the "free state" enzyme reaction kinetics in nanoconfinement
Chen Wang1, De-Kai Ye, Yun-Yi Wang
1State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Abstract:
The investigation of enzyme reaction kinetics in nanoconfined spaces mimicking the conditions in living systems is of great significance. Here, a nanofluidics chip integrated with an electrochemical detector has been designed for studying "free state" enzyme reaction kinetics in nanoconfinement. The nanofluidics chip is fabricated using the UV-ablation technique developed in our group. The enzyme and substrate solutions are simultaneously supplied from two single streams into a nanochannel through a Y-shaped junction. The laminar flow forms in the front of the nanochannel, then the two liquids fully mix at their downstream where a homogeneous enzyme reaction occurs. The "free state" enzyme reaction kinetics in nanoconfinement can thus be investigated in this laminar flow based nanofluidics device. For demonstration, glucose oxidase (GOx) is chosen as the model enzyme, which catalyzes the oxidation of beta-d-glucose. The reaction product hydrogen peroxide (H2O2) can be electrochemically detected by a microelectrode aligning to the end of nanochannel. The steady-state electrochemical current responding to various glucose concentrations is used to evaluate the activity of the "free state" GOx under nanoconfinement conditions. The effect of liquid flow rate, enzyme concentration, and nanoconfinement on reaction kinetics has been studied in detail. Results show that the "free state" GOx activity increases significantly compared to the immobilized enzyme and bath system, and the GOx reaction rate in the nanochannel is two-fold faster than that in bulk solution, demonstrating the importance of "free state" and spatial confinement for the enzyme reaction kinetics. The present approach provides an effective method for exploiting the "free state" enzyme activity in nanospatial confinement.
Related Concept Videos
Enzyme Kinetics
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Introduction to Enzyme Kinetics
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
Fast Reactions
Reaction Mechanisms: Rate-limiting Step Approximation
Enzymes
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Introduction to Mechanisms of Enzyme Catalysis

