title: Determination of glucose oxidase immobilised as monolayer onto a flat surface.
abstract: An assay to estimate the amount of glucose oxidase immobilised as a monolayer onto a flat surface is reported. This method is based on the electrochemical detection of the flavin adenine dinucleotide (FAD) cofactor released by the immobilised enzyme in acid solutions. FAD concentration in the acid solution was measured by amperometry, using a flow injection analysis (FIA) system equipped with a wall-jet electrode, and with a sensitivity of (9.2+/-2.0)x10(-2) nA/nM. By this method, the amount of glucose oxidase molecules present in a monolayer deposited on a silanised glass slide was easily detected, in which the detection limit is more than one order of magnitude lower than the maximum loading of the surface with an ordered monolayer of glucose oxidase.
authors.affiliation: Department of Biological Chemistry, University of Padova, via G. Colombo 3, 35121, Padua, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Vianello
authors.forename: Silvia
authors.initials: S
authors.lastname: Bortoluzzi
authors.forename: Lucio
authors.initials: L
authors.lastname: Zennaro
authors.forename: Adelio
authors.initials: A
authors.lastname: Rigo
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004800:Enzymes, Immobilized / Q000032:analysis*; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D005898:Glass; D005949:Glucose Oxidase / Q000032:analysis*; D018625:Microscopy, Atomic Force / Q000379:methods; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D004800:Enzymes, Immobilized; D005182:Flavin-Adenine Dinucleotide; D005949:Glucose Oxidase