title: Application of the nanogold-4,4'-bis(methanethiol)biphenyl modified gold electrode to the determination of tyrosinase-catechol reaction kinetics in acetonitrile.
abstract: The reactivity of tyrosinase adsorbed on nanogold bound with 4,4'-bis(methanethiol)biphenyl monolayer self-assembled on a gold disk with catechol in a dipolar aprotic solvent, acetonitrile (AN), was studied by cyclic voltammetric and amperometric methods. Tyrosinase exhibited characteristics of a Michaelis-Menten kinetic mechanism. The tyrosinase attached to the nanogold continued to react with substrates in AN even when the water content was lower than 0.01 w/w%. The apparent Michaelis-Menten constant K(m) of tyrosinase for catechol is 5.5 +/- 0.4 mM (n = 5).
authors.affiliation: Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto, Japan. toshion@shinshu-u.ac.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakamura
authors.forename: Jujie
authors.initials: J
authors.lastname: Ren
authors.forename: Kai-mei
authors.initials: KM
authors.lastname: Zhu
authors.forename: Shinshi
authors.initials: S
authors.lastname: Kawara
authors.forename: Baokang
authors.initials: B
authors.lastname: Jin
mesh_terms: D000097:Acetonitriles / Q000032:analysis* / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry*; D004156:Catechol Oxidase / Q000737:chemistry; D002396:Catechols / Q000032:analysis* / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D014442:Monophenol Monooxygenase / Q000032:analysis* / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D001713:Biphenyl Compounds; D004156:Catechol Oxidase; D002396:Catechols; D004800:Enzymes, Immobilized; D006046:Gold; D014442:Monophenol Monooxygenase; D012997:Solvents; D014867:Water; C010574:biphenyl; C034221:catechol; C032159:acetonitrile