Purification and some properties of Mn peroxidase from Lentinula edodes

Two manganese peroxidase isoenzymes MnP1 and MnP2, were produced by the white-rot basidiomycete Lentinula edodes on corncob solid-state cultures under optimized conditions (12 days of incubation at 30 degrees C in corncob solid-state medium supplemented with 0.5% glucose and 5 mM MnSO4). The main isoenzyme, MnP,, was purified to apparent electrophoretic homogeneity by using ultrafiltration, acetone precipitation and gel filtration. MnP, had been purified 6.76-fold with a yield of 26.6%. According to data on gel filtration chromatography and sodium dodecyl sulphate polyacrilamide gel electrophoresis (SDS-PAGE), the molecular weight of the enzyme was 44 kDa. The enzyme is a glycoprotein with 17.8% of its weight in carbohydrates. The optimum pH and temperature of purified MnP were 4.5 and 40 degrees C, respectively. The purified enzyme was stable in the pH range 4.5-6.0 and at temperature up to 45 degrees C. The K-M, values of MnP for hydrogen peroxide and Mn2+ were, at pH 4.5, 20.8 and 22.2 x 10(-3) mM, respectively, and when compared with other MnP enzymes, it was more stable in the presence of high concentrations of H2O2. (c) 2006 Elsevier Ltd. All rights reserved.