8. Protein Function

In hemoglobin, the equilibrium transition from R state to T state is triggered by:

A 9-month old girl with hemolytic anemia is found to have a deficiency in the enzyme responsible for the conversion of molecule-B to pyruvate. Shown below is the oxygen saturation curve for hemoglobin in the erythrocytes of this patient (green curve), compared to the corresponding black curve in normal red blood cells. Which of the following is the most likely explanation for the observed oxygen saturation curve in this patient?

What is the effect of the following changes on the O ₂ affinity of hemoglobin?

A) A drop in the pH of blood plasma from 7.4 to 7.2.

a) Lower the O₂ Affinity.     b) Increase the O₂ Affinity.

B) A decrease in the partial pressure of CO₂ in the lungs from 6 kPa (holding one's breath) to 2 kPa (normal).

a) Lower the O₂ Affinity.      b) Increase the O₂ Affinity.

C) An increase in [BPG] from 5 mM (normal altitudes) to 8 mM (high altitudes).

a) Lower the O₂ Affinity.     b) Increase the O₂ Affinity.