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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 23, Number 3
BKCSDE 23(3)
March 20, 2002 

 
Title
Assembly of Laccase over Platinum Oxide Surface and Application as an Amperometric Biosensor
Author
De Quan, Yousung Kim, Kyung Byung Yoon, Woonsup Shin
Keywords
Laccase, Immobilization, ABTS, PPD, Biosensor.
Abstract
Laccase could be successfully assembled on an amine-derivatized platinum electrode by glutaraldehyde coupling. The enzyme layer formed on the surface does not communicate electron directly with the electrode, but the enzymatic activity of the surface could be followed by electrochemical detection of enzymatically oxidized products. The well-known laccase substrates, ABTS (2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) and PPD (p-phenylenediamine) were used. ABTS can be detected down to 0.5 μM with linear response up to 15 μM and current sensitivity of 75 nA/ μM. PPD showed better response with detection limit of 0.05 μM, linear response up to 20 μM, and current sensitivity of 340 nA/ μM with the same electrode. The sensor responses fit well to the Michaelis-Menten equation and apparent KM values are 0.16 mM for ABTS and 0.055 mM for PPD, which show the enzymatic reaction is the rate-determining step. The laccase electrode we developed is very stable and more than 80% of initial activity was still maintained after 2 months of uses.
Page
385 - 390
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