Question

In a mutant human hemoglobin, a mutation in the β chain abolishes binding of 2,3-bisphosphoglycerate (BPG) to the tetramer. How will this mutation influence the ability of this hemoglobin to give up oxygen at the peripheral tissues? Explain, briefly.

Answer 1

2,3-bisphosphoglycerate (BPG) decreases the affinity of hemoglobin to oxygen, usually at the seas level the Hemoglobin releases only 40% of the oxygen it carries to the tissues, but in hypoxic conditions, the hemoglobin has to release more oxygen to the cells, this is achieved by the action of 2,3-bisphosphoglycerate (BPG), it decreases the affinity of hemoglobin to the oxygen so that more oxygen can be released by the hemoglobin to the cells.

so the mutant human hemoglobin, a mutation in the β chain abolishes binding of 2,3-bisphosphoglycerate (BPG) to the tetramer cannot deliver oxygen to cells in hypoxic ( low oxygen conditions) conditions, for example at high altitudes so so those individuals with the mutation cannot survive in low oxygen concentrations.

Answer 2

In a normal human hemoglobin tetramer, the binding of 2,3-bisphosphoglycerate (BPG) is essential for its function in oxygen transport. BPG binds to the central cavity of the hemoglobin tetramer, where it stabilizes the tense (T) state of hemoglobin. This stabilization facilitates the release of oxygen from the hemoglobin molecules at the peripheral tissues where oxygen concentration is lower.

In the case of the mutant human hemoglobin with a mutation in the β chain that abolishes BPG binding, the ability of hemoglobin to give up oxygen at the peripheral tissues will be impaired. Without BPG, the hemoglobin tetramer will have a higher affinity for oxygen, favoring the relaxed (R) state. This means that the oxygen molecules will bind more tightly to the hemoglobin in the lungs, making it more difficult for hemoglobin to release oxygen at the peripheral tissues.

As a result, the mutant hemoglobin will have a reduced ability to unload oxygen where it is needed most, leading to impaired oxygen delivery to the peripheral tissues. This condition could result in less efficient oxygen supply to organs and tissues, potentially causing various health issues, particularly in situations of increased oxygen demand, such as during physical exertion or at high altitudes.