Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.2 (laccase)
 4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The degradation of the textile dye indigo with purified laccases from the fungi Trametes hirsuta (THL1 and THL2) and Sclerotium rolfsii (SRL1) was studied. All laccases were able to oxidize indigo yielding isatin (indole-2,3-dione), which was further decomposed to anthranilic acid (2-aminobenzoic acid). Based on the oxygen consumption rate of the laccases during indigo degradation, a potential mechanism for the oxidation of indigo involving the step-wise abstraction of four electrons from indigo by the enzyme was suggested. Comparing the effect of the known redox-mediators acetosyringone, 1-hydroxybenzotriazole (HOBT) and 4-hydroxybenzenesulfonic acid (PHBS) on laccase-catalyzed degradation of indigo, we found a maximum of about 30% increase in the oxidation rate of indigo with SRL1 and acetosyringone. The particle size of indigo agglomerates after laccase treatment was influenced by the origin of the laccase preparation and by the incubation time. Diameter distributions were found to have one maximum and compared to the indigo particle size distribution of the control, for all laccases, the indigo agglomerates seemed to have shifted to smaller diameters. Bleaching of fabrics by the laccases (based on K/S values) correlated with the release of indigo degradation products.
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PMID:Indigo degradation with purified laccases from Trametes hirsuta and Sclerotium rolfsii. 1150 Feb 6

Laccase oxidation of phenolic azo dyes was examined with a commercially available laccase from Pyricularia oryzae as the model. Methyl-, methoxy-, chloro-, and nitro-substituted derivatives of 4-(4(prm1)-sulfophenylazo)-phenol were examined as substrates for this laccase. Only the substituents on the phenolic ring were changed. Among the dyes examined, only 2-methyl-, 2-methoxy-, 2,3-dimethyl-, 2,6-dimethyl-, 2,3-dimethoxy-, and 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol served as substrates. Preliminary kinetic studies suggest that 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol is the best substrate. Laccase oxidized the 2,6-dimethyl derivative of 4-(4(prm1)-sulfophenylazo)-phenol to 4-sulfophenylhydroperoxide (SPH) and 2,6-dimethyl-1,4-benzoquinone. The 2-methyl- and 2-methoxy-substituted dyes were oxidized to SPH and either 2-methyl- or 2-methoxy-benzoquinone. Six products were formed from laccase oxidation of the 2,6-dimethoxy-substituted dye. Three of them were identified as SPH, 4-hydroxybenzenesulfonic acid, and 2,6-dimethoxybenzoquinone. A mechanism for the formation of benzoquinone and SPH from laccase oxidation of phenolic azo dyes is proposed. This study suggests that laccase oxidation can result in the detoxification of azo dyes.
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PMID:Phenolic Azo Dye Oxidation by Laccase from Pyricularia oryzae. 1653 91