OXIDATION REACTIONS CATALYZED BY MANGANESE PEROXIDASE ISOENZYMES FROMCERIPORIOPSIS-SUBVERMISPORA

A total of 11 manganese peroxidase isoenzymes (MnP1-MnP11) with isoele ctric points (pIs) in the range of 4.58-3.20 were isolated from liquid - and solid-state cultures of the basidiomycete Ceriporiopsis subvermi spora. In the presence of hydrogen peroxide, these isoenzymes showed d ifferent requirements for Mn(II) in the oxidation of vanillylacetone, o-dianisidine, p-anisidine and ABTS, whereas oxidation of guaiacol by any isoenzyme did not take place when this metal was omitted, K-m valu es for o-dianisidine and p-anisidine in the absence of Mn(II) are in t he range of 0.5-1.0 mM and 4.5-42.0 mM, respectively, Oxalate and citr ate, but not tartrate, accelerate the oxidation of o-dianisidine, both in the presence and in the absence of Mn(II). MnPs from this fungus a re able to oxidize kojic acid without externally added hydrogen peroxi de, indicating that they can also act as oxidases. In this reaction, h owever, the requirement for Mn(II) is absolute.