Pulmonary Physiology, Gas Diffusion & Transport, Dr. D. Penney

Figure 7.07. Changes in the Hb-oxygen association-dissociation curve with temperature, pH and 2-3 DPG.

Increasing temperature decreases the affinity of hemoglobin for oxygen, ie. increases the P50 value. Increasing acidity, or pH, does the same thing. This behavior linked to pH is known as the Bohr Effect.

Unlike hemoglobin, myoglobin displays a hyperbolic curve of loading and unloading oxygen, not sigmoidal.

The curve for hemoglobin is shifted far to the left (lowered P50) when all diphosphoglyceric acid (DPG) is removed. This is called "stripping". The addition of DPG moves the curve to right, decreasing affinity for oxygen and increasing the P50 value.

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