Mn-dependent peroxidase from the lignin-degrading white rot fungus Phlebia radiata

Eija Karhunen (Corresponding Author), Anne Kantelinen, Marja-Leena Niku-Paavola

Research output: Contribution to journalArticleScientificpeer-review

46 Citations (Scopus)


A homogeneous Mn-dependent peroxidase (MnP) was purified from the extracellular culture fluid of the lignin-degrading white rot fungus Phlebia radiata by anion exchange chromatography. The enzyme had a molecular weight of 49,000 and pI 3.8. It was a glycoprotein, containing carbohydrate moieties accounting for 10% of the molecular weight. Mn-peroxidase was capable of oxidizing phenolic compounds in the presence of H2O2, whereas the effect on nonphenolic lignin model compounds was insignificant. MnP contained protoporphyrin IX as a prosthetic group. During enzymatic reactions H2O2 converted the native MnP to compound II. Mn2+ was essential in completing the catalytic cycle by returning the enzyme to its native state. The oxidation of ultimate substrates was dependent on superoxide radicals, O2 and probably on Mn3+ generated during the catalytic cycle. MnP exhibited high activity of NADH oxidation without exogenously added H2O2. It was shown to produce H2O2 at the expense of NADH.

Original languageEnglish
Pages (from-to)25-31
JournalArchives of Biochemistry and Biophysics
Issue number1
Publication statusPublished - 1990
MoE publication typeA1 Journal article-refereed


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