Reaction: 2 Mn(II) + 2 H+ + H2O2 = 2 Mn(III) + 2 H2O
Other name(s): peroxidase-M2; Mn-dependent (NADH-oxidizing) peroxidase
Systematic name: Mn(II):hydrogen-peroxide oxidoreductase
Comments: A hemoprotein. The enzyme from white rot basidiomycetes is involved in the oxidative degradation of lignin. The enzyme oxidizes a bound Mn2+ ion to Mn3+ in the presence of hydrogen peroxide. The product, Mn3+, is released from the active site in the presence of a chelator (mostly oxalate and malate) that stabilizes it against disproportionation to Mn2+ and insoluble Mn4+ [4]. The complexed Mn3+ ion can diffuse into the lignified cell wall, where it oxidizes phenolic components of lignin and other organic substrates [1]. It is inactive with veratryl alcohol or nonphenolic substrates.
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 114995-15-2
References:
1. Glenn, J.K., Akileswaran, L. and Gold, M.H. Mn(II) oxidation is the principal function of the extracellular Mn-peroxidase from Phanerochaete chrysosporium. Arch. Biochem. Biophys. 251 (1986) 688-696.
2. Paszczynski, A., Huynh, V.-B. and Crawford, R. Comparison of ligninase-I and peroxidase-M2 from the white-rot fungus Phanerochaete chrysosporium. Arch. Biochem. Biophys. 244 (1986) 750-765. [PMID: 3080953]
3. Wariishi, H., Akileswaran, L. and Gold, M.H. Manganese peroxidase from the basidiomycete Phanerochaete chrysosporium: spectral characterization of the oxidized states and the catalytic cycle. Biochemistry 27 (1988) 5365-5370.
4. Kuan, I.C. and Tien, M. Stimulation of Mn peroxidase activity: a possible role for oxalate in lignin biodegradation. Proc. Natl. Acad. Sci. USA 90 (1993) 1242-1246. [PMID: 8433984]