Which gas forms carbaminohemoglobin?

Which gas forms carbaminohemoglobin?

• A. Oxygen
• B. Nitrogen
• C. Carbon Monoxide
• D. Carbon Dioxide

Answer: (D)

Carbon dioxide is the gas that forms carbaminohemoglobin. CO2 diffuses into red blood cells and binds directly to the amino terminal groups on the globin chains of hemoglobin, creating carbaminohemoglobin. This binding is favored when hemoglobin is in the deoxygenated state (the Haldane effect), which helps pick up CO2 from tissues and carry it toward the lungs. While most CO2 is transported as bicarbonate in plasma, a fraction remains bound to hemoglobin as carbaminohemoglobin, releasing CO2 in the lungs when hemoglobin becomes oxygenated again. Oxygen binds to the heme iron to form oxyhemoglobin, carbon monoxide binds to heme to form carboxyhemoglobin, and nitrogen is largely inert in this transport context, so it does not form carbaminohemoglobin.

Carbon dioxide is the gas that forms carbaminohemoglobin. CO2 diffuses into red blood cells and binds directly to the amino terminal groups on the globin chains of hemoglobin, creating carbaminohemoglobin. This binding is favored when hemoglobin is in the deoxygenated state (the Haldane effect), which helps pick up CO2 from tissues and carry it toward the lungs. While most CO2 is transported as bicarbonate in plasma, a fraction remains bound to hemoglobin as carbaminohemoglobin, releasing CO2 in the lungs when hemoglobin becomes oxygenated again. Oxygen binds to the heme iron to form oxyhemoglobin, carbon monoxide binds to heme to form carboxyhemoglobin, and nitrogen is largely inert in this transport context, so it does not form carbaminohemoglobin.