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Updated: Oct 1, 2025

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Displacement Statistics of Unhindered Single Molecules Show no Enhanced Diffusion in Enzymatic Reactions
Alexander A Choi1, Ha H Park1, Kun Chen1
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
Abstract:
Recent studies have sparked debate over whether catalytic reactions enhance the diffusion coefficients D of enzymes. Through high statistics of the transient (600 μs) displacements of unhindered single molecules freely diffusing in common buffers, we here quantify D for four enzymes under catalytic turnovers. We thus formulate how ∼ ±1% precisions may be achieved for D, and show no changes in diffusivity for catalase, urease, aldolase, and alkaline phosphatase under the application of wide concentration ranges of substrates. Our single-molecule approach thus overcomes potential limitations and artifacts underscored by recent studies to show no enhanced diffusion in enzymatic reactions.
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