Progesterone binding to the tryptophan residues of human α1-acid glycoprotein

Binding studies between progesterone and α1-acid glycoprotein allowed us to demonstrate that the binding site of progesterone contains one hydrophobic tryptophan residue and that the structure of the protein is not altered upon binding. The data obtained at saturated concentrations of progesterone clearly reveals the type of interaction at physiological levels.