Microhetero;geneity and polymorphism of human serum thryroxine-binding globulin. Study by isoelectric focusing and radioprint immunofixation.

A new technique of radioprint immunofixation following isoelectric focusing was applied to the study of microheterogeneity of thyroxine-binding globulin without purification, in individual sera; this protein appeared to give rise to at least seven bands with isoelectric points in the range of pI 4.2--5.0. Furthermore, two different distributions of the intensity of these bands were found in the sera investigated, suggesting the existence of thyroxine-binding globulin polymorphism in man.