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Name: Betty
Status: Student
Age: 15
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Date: March 2004

Where does carbon monoxide bind to hemoglobin?

Like oxygen, carbon monoxide binds to the iron atoms of the hemoglobin molecules that are inside the red blood cells but the binding of carbon monoxide to the iron is much stronger ( about 210 times stronger) than that of oxygen. The binding of carbon monoxide to iron is responsible for asphyxiation from carbon monoxide poisoning. Once carbon monoxide binds to the iron it pretty much knocks that molecule out of operation...breath fresh air!


Both oxygen and carbon monoxide are bound to hemoglobin at the iron atom in the center of the protein. Oxygen doesn't dissolve well in water, so therefore needs to be bound to a carrier in the blood. Hemoglobin binds oxygen only slightly, which is good, because it needs to carry it around through the blood but then needs to let go of it at the destination. Carbon monoxide binds to the iron in hemoglobin much more easily and sticks to it very tightly. So if there is oxygen and carbon monoxide " fighting" for spaces in the hemoglobin, CO will win and as it circulates, it doesn't let go.


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