A manganese peroxidase from the white-rot fungus Phanerochaete crassa WD1694, that had exhibited
very high ability to bleach unbleached kraft pulp, was purified and characterized. The MnP was purified
by adsorption-desorption on DEAE-Sepahrose CL-6B and FPLC on DEAE-Toyopearl. The purified MnP
gave a single band at 48.3 kDa on SDS-PAGE and could be separated into four isozymes at extremely
close pIs (pI4.61, 4.59, 4.52, 4.50) by isoelectric focusing. The N-terminal sequences of the four isozymes
were highly homologous and similar to those of the MnPs from P. chrysosporium. The enzyme oxidized
2,6-dimethoxyphenol (DMP) with and without Mn(Ⅱ) but did not oxidize veratryl alcohol. The optimal
pH of P. crassa WD1694 MnP was 3.0-4.0 and lower than that (4.5-5.0) of P. chrysosporium and P.
sordida MnPs. Apparent Km values for oxidation of Mn(Ⅱ) and DMP without Mn(Ⅱ) were 35.8×10-3 mM
and 30.7 mM, respectively. These results showed that the MnP from P. crassa WD1694 was very similar
to the MnPs from P. chrysosporium in terms of catalytic properties and N-terminal sequences.