Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis
Open Access
- 1 June 2012
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nanoscale Research Letters
- Vol. 7 (1), 287
- https://doi.org/10.1186/1556-276x-7-287
Abstract
In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee > 99%) synthesis of (S)-7-hydroxy-2-tetralol.Keywords
This publication has 50 references indexed in Scilit:
- Polytetrafluorethylene-Au as a substrate for surface-enhanced Raman spectroscopyNanoscale Research Letters, 2011
- Enzyme:Nanoparticle Bioconjugates with Two Sequential Enzymes: Stoichiometry and Activity of Malate Dehydrogenase and Citrate Synthase on Au NanoparticlesLangmuir, 2010
- Immobilization of Thermoanaerobium brockii alcohol dehydrogenase on SBA-15Bioprocess and Biosystems Engineering, 2010
- Effect of refluxed silver nanoparticles on inhibition and enhancement of enzymatic activity of glucose oxidaseColloids and Surfaces A: Physicochemical and Engineering Aspects, 2009
- Enzyme stability and stabilization—Aqueous and non-aqueous environmentProcess Biochemistry, 2008
- Improvement of enzyme activity, stability and selectivity via immobilization techniquesEnzyme and Microbial Technology, 2007
- Molecular hydrogel-immobilized enzymes exhibit superactivity and high stability in organic solventsChemical Communications, 2007
- Recent developments in asymmetric reduction of ketones with biocatalystsTetrahedron: Asymmetry, 2003
- Unusual stereoselectivity in the reduction of bicyclo[3.3.0]oct-2-en-8-one by Thermoanaerobiumbrockii alcohol dehydrogenaseJournal of the Chemical Society, Chemical Communications, 1991
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976