title: Association of Yeast Alcohol Dehydrogenase with Superparamagnetic Nanoparticles: Improving the Enzyme Stability and Performance.
abstract: Alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae was covalently attached, via glutaraldehyde, to magnetite nanoparticles (MagNP) previously coated with aminopropyltriethoxysilane (MagNP/APTS), or with a silica shell followed by the APTS coating (MagNP@SiO2/APTS). In both cases, a great improvement of enzymatic activity has been observed for the ethanol-acetaldehyde conversion. The MagNP@SiO2/APTS-ADH system exhibited the best stability with respect to pH and temperature. Its residual activity after 10 successive recovery cycles and 24 h storage, was maintained around 80% in comparison with 20% for the MagNP/APTS system, and a null activity for free ADH. Luminescence measurements for the immobilized enzyme indicated the occurrence of conformational changes on ADH, contributing for its improved catalytic performance.
authors.forename: Caterina G C Marques
authors.initials: CG
authors.lastname: Netto
authors.forename: Leandro H
authors.initials: LH
authors.lastname: Andrade
authors.forename: Rafael S
authors.initials: RS
authors.lastname: Freitas
authors.forename: Henrique E
authors.initials: HE
authors.lastname: Toma
mesh_terms: D000079:Acetaldehyde; D000426:Alcohol Dehydrogenase / Q000737:chemistry*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D000431:Ethanol; D006863:Hydrogen-Ion Concentration; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D058185:Magnetite Nanoparticles; D000431:Ethanol; D012822:Silicon Dioxide; D000426:Alcohol Dehydrogenase; D000079:Acetaldehyde