Catalyzes the oxidation of Mn(2+) to Mn(3+). The latter, acting as a diffusible redox mediator, is capable of oxidizing a variety of lignin compounds. Manganese peroxidase H4 MAFGSLLAFVALAAITRAAPTAESAVCPDGTRVTNAACCAFIPLAQDLQETLFQGDCGEDAHEVIRLTFHDAIAISQSLGPQAGGGADGSMLHFPTIEPNFSANSGIDDSVNNLLPFMQKHDTISAADLVQFAGAVALSNCPGAPRLEFMAGRPNTTIPAVEGLIPEPQDSVTKILQRFEDAGNFSPFEVVSLLASHTVARADKVDETIDAAPFDSTPFTFDTQVFLEVLLKGTGFPGSNNNTGEVMSPLPLGSGSDTGEMRLQSDFALARDERTACFWQSFVNEQEFMAASFKAAMAKLAILGHSRSSLIDCSDVVPVPKPAVNKPATFPATKGPKDLDTLTCKALKFPTLTSDPGATETLIPHCSNGGMSCPGVQFDGPA 382 MP-I PEM4_PHACH Peroxidase manganese-dependent H4