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A New Laccase Biosensor For Polyphenols Determination
CECUL -Faculdade de Ciências da Universidade de Lisboa, Campo Grande, C 8 1749-016 Lisboa, Portugal
* Author to whom correspondence should be addressed.
Received: 1 April 2003; Accepted: 5 May 2003 / Published: 29 June 2003
Abstract: The relevance of polyphenols in human health is a well known fact. Prompted by that, a very intensive research has been directed to get a method to detect them, wich will improve the current ones. Laccase (p-diphenol:dioxygen oxidoreductase EC 18.104.22.168) is a multi-copper oxidase, wich couples catalytic oxidation of phenolic substrates with four electron reduction of dioxygen to water . A maximum catalytic response in oxigenated electrolyte was observed between 4.5 and 5.5 , while for pH > 6.9 the laccase was found to be inactive . We prepared a biosensor with laccase immobilised on a polyether sulphone membrane, at pH 4.5, wich was applied at Universal Sensors base electrode. Reduction of the product of oxidation of several polyphenols, catalysed by laccase, was done at a potential for wich the polyphenol of interest was found to respond. Reduction of catechol was found to occur at a potential of -200mV, wich is often referred to in the literature for polyphenolic biosensors. However other polyphenols did not respond at that potential. It was observed that (+)- catechin produced a very large cathodic current when +100mV were applied to the laccase biosensor, both in aqueous acetate and 12% ethanol acetate buffer, whereas caffeic acid responded at -50mV. Other polyphenols tested were gallic acid, malvidin, quercetin, rutin, trans-resveratrol
Keywords: Biosensor; Laccase; Polyphenol; (+)- catechin; Caffeic acid
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Cite This Article
MDPI and ACS Style
Gomes, S.A.; Rebelo, M.J. A New Laccase Biosensor For Polyphenols Determination. Sensors 2003, 3, 166-175.
Gomes SA, Rebelo MJ. A New Laccase Biosensor For Polyphenols Determination. Sensors. 2003; 3(6):166-175.
Gomes, S. A.; Rebelo, M. J. 2003. "A New Laccase Biosensor For Polyphenols Determination." Sensors 3, no. 6: 166-175.