title: Enzyme renaturation to higher activity driven by the sol-gel transition: Carbonic anhydrase.
abstract: We describe a so-far unknown route for renaturing denatured enzymes, namely subjecting the denatured enzyme to an oxide sol-gel transition. The phenomenon was revealed in a detailed study of denatured carbonic anhydrase which was subjected to an alumina sol-gel transition, up to the thermally stabilizing entrapment in the final xerogel. Remarkably, not only that the killed enzyme regained its activity during the sol-gel process, but its activity increased to 180% of the native enzyme. To the best of our knowledge, this is the first report of enhanced activity following by renaturing (a "Phoenix effect"). Kinetic study which revealed a five-orders of magnitude (!) increase in the Arrhenius prefactor upon entrapment compared to solution. Circular dichroism analysis, differential scanning calorimetry, zeta potential analyses as well as synchronous fluorescence measurements, all of which were used to characterize the phenomenon, are consistent with a proposed mechanism which is based on the specific orienting interactions of the active site of the enzyme with respect to the alumina interface and its pores network.
authors.affiliation: Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, St. Petersburg, 197101, Russian Federation.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Vinogradov
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Avnir
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002256:Carbonic Anhydrases / Q000378:metabolism*; D020134:Catalytic Domain / Q000502:physiology*; D002417:Cattle; D002942:Circular Dichroism; D004789:Enzyme Activation; D004793:Enzyme Reactivators; D053758:Nanoparticles / Q000737:chemistry; D044367:Phase Transition; D020673:Protein Renaturation; D013050:Spectrometry, Fluorescence
chemical_list: D004793:Enzyme Reactivators; D002256:Carbonic Anhydrases; D000537:Aluminum Oxide