Question

What is the physiological relevance of the Bohr effect and BPG?

Short answer

The Bohr effect and BPG are important in binding O₂ with hemoglobin and releasing O₂ from hemoglobin.

Step-by-step solution

The Bohr effect

The Bohr effect states that when CO₂ is present, hemoglobin's affinity for oxygen decreases. Due to its higher affinity for hemoglobin than oxygen, CO₂ displaces oxygen from the heme when levels rise. Since the tissues contain a lot of CO₂, the oxygen released to the tissues is enhanced.

BPG

BPG is a compound that binds to deoxyhemoglobin tightly but to oxyhemoglobin very weakly.2, 3 BPG shifts the equilibrium towards the T-state because it binds to the deoxyhemoglobin's central cavity, thus decreasing hemoglobin's oxygen affinity.

In the absence of BPG, very little oxygen is released since hemoglobin's O₂-binding affinity is very high. In the presence of BPG, hemoglobin releases its bound O₂ effectively.