Metmyoglobin

Metmyoglobin is a form of the oxygen-carrying protein myoglobin, which is found in muscle tissue. It is produced when myoglobin is exposed to certain chemicals or undergoes changes in pH or temperature. Metmyoglobin is unable to bind oxygen, which can lead to a condition known as metmyoglobinemia if it accumulates in the body.

Structure

Metmyoglobin is structurally similar to myoglobin, with a single polypeptide chain and a heme group. However, in metmyoglobin, the iron atom in the heme group is in the ferric (Fe3+) state, rather than the ferrous (Fe2+) state found in myoglobin. This change in oxidation state prevents metmyoglobin from binding oxygen.

Formation

Metmyoglobin forms when myoglobin is exposed to oxidizing agents, such as hydrogen peroxide or nitrite. Changes in pH or temperature can also cause myoglobin to convert to metmyoglobin. In addition, certain genetic conditions can increase the body's production of metmyoglobin.

Metmyoglobinemia

Metmyoglobinemia is a condition characterized by an excess of metmyoglobin in the blood. This can occur as a result of certain genetic conditions, exposure to certain drugs or chemicals, or severe muscle injury. Symptoms can include cyanosis (a bluish coloration of the skin), fatigue, and shortness of breath. Treatment typically involves addressing the underlying cause of the condition.

See also

• Myoglobin
• Hemoglobin
• Metmyoglobin reductase

Metmyoglobin Resources
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