Purification and characterisation of laccase from the medicinal wild mushroom Coriolus brevis.

Laccases are enzymes that catalyse oxidation of various aromatic compounds, with potential industrial and environmental applications. Here, a novel laccase, Cb Laccase, was purified to homogeneity from the medicinal wild mushroom Coriolus brevis using standard chromatographic procedures. The overall yield was approximately 11 %. Gel filtration and sodium dodecyl sulphate–polyacrylamide gel electrophoresis revealed that Cb Laccase is a monomer with a molecular mass of 51 kDa. The optimal reaction pH with 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) as a substrate was low (pH 2.5), and the optimal reaction temperature was relatively high (70 °C). The enzyme exhibited very low K m (0.02 mM) and high catalytic efficiency (7.2 × 106) with syringaldazine, and its substrate specificity followed the order: syringaldazine > o -dianisidine > 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) > 2,6-dimethoxyphenol > catechol. Addition of 1 mM Cu2+ enhanced the enzymatic activity, whereas dithiothreitol, sodium azide, and diethyldithiocarbamic acid significantly inhibited it. The enzyme was highly stable at high temperatures, over a wide range of pH values, and in the presence of various detergents. These findings suggest that Cb Laccase is distinct from laccases previously purified from other sources and may be useful for the degradation of environmental pollutants. [Display omitted] • Cb Laccase was purified from Coriolus brevis and then characterized. • It was a 51-kDa monomeric enzyme with varying specificities across substrates. • It was stable at high temperatures, over a wide pH range, and in detergents. • It could potentially be applicable in environmental pollutant degradation studies. [ABSTRACT FROM AUTHOR]