<unk>  (pronounced MET-hemoglobin) is a form of the oxygen-carrying protein hemoglobin (British English: haemoglobin), in which the iron in the heme group is in the Fe3+ state, not the Fe2+ of normal hemoglobin.<unk>  is unable to carry oxygen. It is chocolate-brown in color. The NADH-dependent enzyme<unk>  reductase (AKA diaphorase I) is responsible for converting<unk>  back to hemoglobin.
Normally one to two percent of people's hemoglobin is<unk> ; a higher percentage than this can be genetic or caused by exposure to various chemicals and depending on the level can cause health problems known as<unk> emia. A higher level of<unk>  will tend to cause a pulse oximeter to read closer to 85% regardless of the true level of oxygen saturation.
Methaemoglobin
Hemoglobin
Hemocyanin
Fulminic acid
Glycobiarsol
Toxidrome
Choline theophyllinate
Hemin