Direction: The binding efficiency of three different receptorsR1, R2 and R3 were tested against a ligand using equilibrium dialysis, with a constant concentration of receptor and varying concentrations of ligand. The Scatchard plot of receptor titration with different concentration of ligand is given below (r is moles of bound ligand per moles of receptor and c is concentration of free ligand)
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Which one of the receptors has thehighestaffinity for the ligand?
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- R1
- R2
- R3
- R4
Correct Option: A
Analysing the graph it can be seen that r/c value is the maximum for Recpetor1. Here, r is the moles of bound ligand per moles of receptor and c is concentration of free ligand. So, more the value of r/c, more will be the efficiency of binding the ligand by a receptor. Since r/c for Recpetor1 is 4 which is the highest, so Receptor1 is the most efficient binder of the ligand.
