[Term] id: PR:000060250 name: methemoglobin def: "A hemoglobin complex in which the iron of the heme prosthetic group is in the ferric (Fe3+) state rather than the normal ferrous (Fe2+) state." [PRO:DAN, Wikipedia:Methemoglobin] comment: Category=complex. Note: When normal hemoglobin carries oxygen, the iron(II) oxidizes to iron(III). In methemoglobin, the iron is in the iron(III) state in the absence of oxygen. synonym: "metHb" EXACT PRO-short-label [PRO:DAN] synonym: "ferric Hb" EXACT [] synonym: "ferrihaemoglobin" EXACT [] synonym: "ferrihemoglobin" EXACT [] xref: CHEBI:17423 is_a: GO:0005833 ! hemoglobin complex relationship: non-covalently_bound_to CHEBI:26689 {cardinality="0"} ! singlet dioxygen relationship: has_component CHEBI:38574 {cardinality="4"} ! ferriheme relationship: has_component PR:000020113 {cardinality="2"} ! hemoglobin subunit alpha, initiator methionine removed form relationship: has_component PR:000020114 {cardinality="2"} ! hemoglobin subunit beta, initiator methionine removed form