Affinity chromatography is a method that can be used to purify cell-surface receptors, while they retain their hormone-binding ability. A ligand (hormone) for a receptor of interest is chemically linked to polystyrene beads. A solubilized preparation of membrane proteins is passed over a column containing these beads. Only the receptor binds to the beads.
When an excess of the ligand (hormone) is poured through the column after the receptor binding step, what do you expect will occur?
A) The ligand will attach to those beads that have the receptor and remain on the column.
B) The ligand will cause the receptor to be displaced from the beads and eluted out.
C) The ligand will attach to the bead instead of the receptor.
D) The ligand will cause the bead to lose its affinity by changing shape.
E) The reaction will cause a pH change due to electron transfer.
Steroid hormone interacting with an intracellular receptor.
Attributed to Apollodorus, Column of Trajan, Rome (detail).
A simplified view of ligand binding and conformation energies in hemoglobin
Steroid hormone receptors
Mechanisms of Hormone Action
Prove the following arguments using the two-column format.