title: Substrate-dependent kinetics in tyrosinase-based biosensing: amperometry vs. spectrophotometry.
abstract: Despite the broad use of enzymes in electroanalytical biosensors, the influence of enzyme kinetics on the function of prototype sensors is often overlooked or neglected. In the present study, we employ amperometry as an alternative or complementary method to study the kinetics of tyrosinase, whose catalytic activity results in o-quinone products. We further compare our results for four monophenolic substrates with those obtained from ultraviolet-visible spectrophotometry and show that the results from both assays are in good agreement. We also observe large variations in the enzyme kinetics for different monophenolic substrates depending on the R-group at the para position. To further study this effect, we investigate the stability of quinone products in the enzymatic assay. This information can in principle be utilized to discriminate between different phenolic species by monitoring the reaction rate.
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: Liza
authors.initials: L
authors.lastname: Rassaei
authors.forename: Jin
authors.initials: J
authors.lastname: Cui
authors.forename: Edgar D
authors.initials: ED
authors.lastname: Goluch
authors.forename: Serge G
authors.initials: SG
authors.lastname: Lemay
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013379:Substrate Specificity
chemical_list: D014442:Monophenol Monooxygenase