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Laccase chloride inhibition reduction by an anthraquinonic substrate

Paper ID Volume ID Publish Year Pages File Format Full-Text
17326 42660 2011 9 PDF Available
Title
Laccase chloride inhibition reduction by an anthraquinonic substrate
Abstract

Due to their low substrate specificity, fungal laccases have a great potential in industrial applications, including the bioremediation of colored wastewaters from textile industry. However, the presence of halides in these effluents (up to 1 M NaCl) which inhibit laccases is a drawback for bioremediation processes. In order to develop an efficient enzymatic remediation process for textile dye effluent, the possibility to reduce this halide inhibition is conditioned by a better understanding of the phenomenon. The present study gives a detailed account of the kinetics of chloride inhibition of both ABTS (a model substrate) and ABu62 (an anthraquinonic acid dye) oxidations catalyzed by Trametes versicolor laccase (LacIIIb). Chloride inhibition can be described by a mixed model for ABTS and a non-competitive model for ABu62 and both inhibitions are linear suggesting a single inhibitory site for chloride. Experiments were also conducted in presence of both substrates. An apparent activation of laccase was observed in the presence of ABu62 leading to an enhancement of the oxidation rate of ABTS. The extent of activation increased in the presence of chloride anions. Finally, for the first time to our knowledge, we evidenced that inhibition of ABTS oxidation by chloride can be reduced in the presence of ABu62.

► Laccase-catalyzed ABu62 oxidation does not follow Michaelis-Menten kinetic behavior. ► Up to 80 μM, ABu62 increases ABTS oxidation rate. ► Laccase inhibition by NaCl is mixed toward ABTS and non-competitive toward ABu62. ► NaCl inhibition of ABTS oxidation is reduced by ABu62 but not totally overcome.

Keywords
ABu62, sodium 1-amino-4-(cyclohexylamino)-9,10-dihydro-9,10-dioxoanthracene-2-sulphonate; ABTS, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); IC50, inhibitor concentration leading to a 50% decrease of laccase activity; LacIIIb, laccase from Tram
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Laccase chloride inhibition reduction by an anthraquinonic substrate
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 49, Issues 6–7, 10 December 2011, Pages 517–525
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us