title: Electrical activity of cellobiose dehydrogenase adsorbed on thiols: Influence of charge and hydrophobicity.
abstract: The interface between protein and material surface is of great research interest in applications varying from implants, tissue engineering to bioelectronics. Maintaining functionality of bioelements depends greatly on the immobilization process. In the present study direct electron transfer of cellobiose dehydrogenase from Humicola insolens (HiCDH), adsorbed on four different self-assembled monolayers (SAMs) formed by 5-6 chain length carbon thiols varying in terminal group structure was investigated. By using a combination of quartz crystal microbalance with dissipation, ellipsometry and electrochemistry the formation and function of the HiCDH film was studied. It was found that the presence of charged pyridinium groups was needed to successfully establish direct electron contact between the enzyme and electrode. SAMs formed from hydrophilic charged thiols achieved nearly two times higher current densities compared to hydrophobic charged thiols. Additionally, the results also indicated proportionality between HiCDH catalytic constant and water content of the enzyme film. Enzyme films on charged pyridine thiols had smaller variations in water content and viscoelastic properties than films adsorbed on the more hydrophobic thiols. This work highlights several perspectives on the underlying factors affecting performance of immobilized HiCDH.
authors.affiliation: Department of Chemistry, University of Rochester, 14611 Rochester, NY, USA. Electronic address: plamberg@ur.rochester.edu.
authors.forename: P
authors.initials: P
authors.lastname: Lamberg
authors.affiliation: CMC Diabetes Formulation Development, Novo Nordisk, Novo Alle Bagsvaerd, 2880, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Hamit-Eminovski
authors.affiliation: Protein Engineering, Novozymes A/S, Bagsvaerd 2880, Denmark.
authors.forename: M D
authors.initials: MD
authors.lastname: Toscano
authors.affiliation: Department of Organic Chemistry, Center for Physical Sciences and Technology, Sauletekio av. 3, LT-10257 Vilnius, Lithuania.
authors.forename: O
authors.initials: O
authors.lastname: Eicher-Lorka
authors.affiliation: Department of Organic Chemistry, Center for Physical Sciences and Technology, Sauletekio av. 3, LT-10257 Vilnius, Lithuania.
authors.forename: G
authors.initials: G
authors.lastname: Niaura
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Arnebrant
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Shleev
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Ruzgas
mesh_terms: D000327:Adsorption; D001203:Ascomycota / Q000201:enzymology; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry* / Q000378:metabolism*; D002384:Catalysis; D004548:Elasticity; D004563:Electrochemistry / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D058525:Quartz Crystal Microbalance Techniques; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D013438:Sulfhydryl Compounds; D006046:Gold; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase
keywords: Cellobiose dehydrogenase; Direct electron transfer; Hydrophobicity; Self-assembled monolayers; Surface charge; Thiol