Oxygen Myoglobin Dissociation Curve
CO2 effect on Oxygen-Hemoglobin Dissociation Curve
How pCO2 Affects Oxy-Hemoglobin Dissociation Curve:
- The animations show how the concentration of carbon dioxide in the plasma (partial pressure of CO2 or pCO2) affects oxygen-hemoglobin dissociation curve (O2-Hb saturation).
- As the graphs reveal, high pCO2 has the same effect on the O2-Hb dissociation curve as low plasma pH and low pCO2 has the same effect as high plasma pH (= Bohr effect).
- High pCO2 lessens hemoglobin’s affinity for O2 in two ways.
- First, carbon dioxide is converted to H+ and bicarbonate ion in red blood cells via the enzyme carbonic anhydrase.
- The H+ ions bind to hemoglobin amino acids, and the alteration makes it more difficult for O2 to also associate.
- Secondly, some of the carbon dioxide binds directly to hemoglobin amino acids. This also causes alteration to the hemoglobin that make it more difficult for O2 to bind.