Manganese peroxidase

Manganese peroxidase (commonly referred to as MnP) was discovered in 1985 simultaneously by the research groups of Michael H. Gold[1] and Ronald Crawford[2] in the fungus Phanerochaete chrysosporium.

[3] The enzyme is thought to be unique to Basidiomycota as no bacterium, yeast, or mold species has yet been found which naturally produces it.

MnP catalysis occurs in a series of irreversible oxidation-reduction (redox) reactions which follow a ping-pong mechanism with second order kinetics.

There the oxygen in H2O2 binds to an Fe(III) ion in the heme cofactor to form an iron peroxide complex.

Two electrons are transferred from Fe3+ to peroxide, breaking the oxygen-peroxide bond to form H2O and a Fe(IV) oxo-porphyrin radical complex.

The Mn(III) chelate interacts with the active site to facilitate product release from the enzyme.

There are a total of 357 amino acid residues in the MnP of P. chrysosoporium, and a similar number in enzymes produced by other basidiomycetes.

[10] For this purpose, basidiomycetes secrete MnP, rather than Mn(III), and the enzyme functions outside of the fungal cell.

Sketch of manganese peroxidase mechanism showing the initial state, iron peroxide complex, and Compounds I and II. Here, the heme cofactor is represented via an iron-nitrogen complex. The Fe(IV) oxo-porphyrin radical resonates throughout the heme.
Structure of manganese peroxidase. Bounded manganese and calcium ions are highlighted in purple and pink, respectively.