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Electrode Reactions of Catechol at Tyrosinase‐Immobilized Latex Suspensions
Author(s) -
Rijiravanich Patsamon,
Aoki Koichi,
Chen Jingyuan,
Surareungchai Werasak,
Somasundrum Mithran
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200302798
Subject(s) - tyrosinase , catechol , chemistry , polystyrene sulfonate , polystyrene , catalysis , immobilized enzyme , adsorption , polymer chemistry , organic chemistry , enzyme , layer (electronics) , polymer , pedot:pss
Tyrosinase was immobilized on polystyrene latex particles in order to control amounts of the enzyme. The tyrosinase‐coated latex particles were composed of the core polystyrene and four successive coating layers: polystyrene sulfonate, polyallylamine, tyrosinase and polyallylamine again, built up by the layer‐by‐layer technique. They showed catalytic currents for the enzymatic oxidation of catechol to o ‐quinone. The enzyme activity per particle was evaluated as 2.3×10 −7 units from UV absorption of o ‐quinone. The relation between the catalytic current and the concentration of catechol leads to a Michaelis‐Menten type kinetic equation. The layer‐by‐layer method was found to have a deactivating effect on enzyme catalysis. In spite of this, the catechol oxidation current was larger than the current from free tyrosinase at a common value of enzyme units per volume. This is ascribed to strong adsorption of the latex particles on the electrode, leading to the enhancement of the local concentration of tyrosinase.