Mn-Peroxidase from Bjerkandera adusta 90-41. Purification and Substrate Specificity

E. I. Dzedzyulya^1* and E. G. Becker²

¹Department of Mycology and Algology, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (7-095) 939-0997; E-mail: kdz@enzyme.chem.msu.ru

²Department of Chemical Enzymology, School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (7-095) 939-0997; E-mail: lbecker@enzyme.chem.msu.su

^* To whom correspondence should be addressed.

Received September 9, 1999; Revision received October 28, 1999

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Mn-peroxidase has been purified to homogeneity from culture liquid of white-rot fungus Bjerkandera adusta 90-41 grown on medium containing lignosulfonates. According to the data on SDS-PAGE and isoelectrofocusing, the molecular mass of the enzyme is 43 kD and the isoelectric point is 3.5. The pH-optimum in the reaction of MnSO₄ oxidation is 4.5. The substrate specificity of the enzyme has been studied. In contrast to previously known Mn-peroxidases from B. adusta, the isolated enzyme has no activity with veratryl alcohol. The enzyme can oxidize ammonium 2,2-azino-bis(ethyl-6-benzothiazoline sulfonate) (ABTS), o-phenylenediamine, and phenol red in the absence of Mn²⁺. Oxidation of ABTS and o-phenylenediamine is stimulated by Mn²⁺, whereas in the reaction of oxidation of phenol red Mn²⁺ acts as an inhibitor. Some aromatic substrates, such as pyrocatechol and guaiacol, are oxidized only in the presence of Mn²⁺.

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KEY WORDS: Mn-peroxidase, lignin degradation, white-rot fungus, Bjerkandera adusta

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