Purification of lignin peroxidase from <i>Hexagona tenuis</i> MTCC-1119 and its kinetic properties in aqueous medium containing miscible organic solvents

Abstract

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Lignin peroxidase from culture filtrate of a new lignolytic fungal strain <i>Hexagona tenuis</i> MTCC-1119 has been purified to homogeneity using a simple procedure. The molecular wt. of the enzyme has been found to be 48 kDa using SDS-PAGE analysis. The enzymatic characteristics like Km, <i style="">p</i>H and temperature optima of the enzyme using veratryl alcohol, <i style="">n</i>-propanol and H₂O₂ as substrate has been determined. The Km values have been found to be 70μM, 80μM and 530μM for veratryl alcohol, H₂O₂and <i style="">n</i>-propanol respectively. The <i style="">p</i>H and temperature optima were 3 and 30°C respectively. The enzyme retains 50% of its activity in 10% of the water miscible organic solvents acetone, dioxane, diethyl ether, acetonitrile and dimethyl formamide in aqueous medium. The inhibition of the enzyme by acetone has been found to be reversible and uncompetitive with inhibition constant K_Ivalues 2.72 mM, 2.96 mM and 0.34 mM using veratryl alcohol, hydrogen peroxide and <i style="">n</i>-propanol as the substrates respectively.

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