Converts oxalate to formate and CO(2) in an O(2)-dependent reaction. Can also catalyze minor side reactions: oxalate oxidation to produce H(2)O(2), and oxalate-dependent, H(2)O(2)-independent dye oxidations. H(+) + oxalate = CO2 + formate Binds 2 manganese ions per subunit. Expression is up-regulated in presence of human keratinocytes.