RESUMO
Two manganese peroxidase (MnP) active fractions D1 and D2 were got from the extracellular culture of Trametes versicolor by using ammonium sulfate precipitation, DEAE-cellulose DE52 chromatography. MnP1 was purified to electrophoretic homogeneity from the D2 by Phenyl Sepharose 6 Fast Flow chromatography and MnP2 was purified to electrophoretic homogeneity from the D1 by Sephacryl S-200HR chromatography and Phenyl Sepharose 6 Fast Flow chromatography. The specific activities of two MnP isozymes are 579.1U/mg and 425.0U/mg; purification folds are 17.51 and 12.85 and the yields are 6.17% and 2.47%, respectively. MnP1 and MnP2 have approximate molecular masses of 46.3kD and 43.0kD respectively, as determined by SDS-PAGE. The isoenzymes differed in optimum temperature (60degreesC and 65degreesC) and optimum pH(5.8 and 6.2) for oxidation of DMP (2,6-dimethoxyphenol). MnP1 and MnP2 are stable below 45degreesC and ranging from pH4.0 to pH7.0. DMP is the best substrate, the Km values of MnP1 and MnP2 for DMP are 13.43micromol/L and 12.45micromol/L respectively. Catalysis doesn't occur in the complete absence of Mn. EDTA inhibites the activities of MnP1 and MnP2 at the higher concentration and DTT inhibites the enzyme activities completely.
