Before revision: We demonstrate that the oft-reported enhanced diffusion of certain enzymes at substrate concentrations above biological concentrations, meaning above kM(the Michaelis-Menten constant ), can be accounted for by dissociation of these oligomericenzymes into their smaller subunits. Our measurements based on using four independent techniques, static light scattering, dynamic light scattering (DLS), size-exclusion chromatography (SEC), and fluorescence correlation spectroscopy (FCS) , lead to this conclusion for the enzymes urease (emphasized in the main text ), and hexokinase and acetylcholinesterase (data shown in the supplementary material), each of which catalyzes different reactions.
After revision: We demonstrate that the oft-reported enhanced diffusion of certain enzymes at substrate concentrations above biological concentrations, meaning above kM(the Michaelis-Menten constant ), can be accounted for by dissociation of these oligomericenzymes into their smaller subunit fragments that diffuse more rapidly, thus providing a simple physical mechanism of enhanced diffusion in this regime of concentrations. Mindful that this conclusion may be controversial, our findings are sup-ported by four independent analytical techniques, static light scattering, dynamic light scattering (DLS), size-exclusion chromatography (SEC), and fluorescence correlation spectroscopy (FCS) , lead to this conclusion for the enzymes urease (emphasized in the main text ), and hexokinase and acetylcholinesterase (data shown in the supplementary material), each of which catalyzes different reactions.