Question

Question 31 6 pts 16) Some patients with erythrocytosis (excess Red Blood Cells) have a mutation that converts a Lysine to Alanine at residue 82 in the beta-subunit of hemoglobin. This particular Lysine normally protrudes in the central cavity of deoxyhemoglobin, where it participates in binding 2,3,-bisphosphoglycerate (BPG). What effect would you predict this mutation will have on a) the affinity of hemoglobin for BPG and for b) the affinity of hemoglobin for Oxygen in patients with erythrocytosis? Briefly explain your answers BIVA -A- IEE 3 - 2 + 11 12pt * * Paragraph -

Answer 1

Ans a) The 2,3-biphosphoglycerate binding is responsible for stabilisation of T-state of haemoglobin i.e deoxyhaemoglobin. Hence, a mutation from lysine to alanine will decrease the affinity for 2,3-BPG, leading to less binding and destabilisation of T-state.

Ans b) The affinity for oxygen will increase because of destabilisation of deoxyhaemoglobin state i.e T- state.