The identification of serum ligand-binding proteins using immuno-precipitation techniques and autoradiography

The identification of ligand-binding proteins in serum is important for understanding many metabolic pathways and for interpreting clinical measurements. Most techniques presently available lack the facility to identify specific binding proteins. This problem has been overcome by combining the specificity of immunological methods with the sensitivity of radioisotope detection. The methods comprise an adaptation of 2-dimensional immuno-electrophoresis, and radial immunodiffusion, combined with radiolabelled ligands and autoradiography. They have been used to determine the serum binding of calcium, cadmium, thyroxine and the beta blocking drug propranolol. This technique has wide application to other ligand-binding interactions.