Oestrone binding properties of nine molecular variants of rat alpha-foetoprotein

Rat alpha-foetoprotein was separated into nine molecular variants by electrophoresis and affinity chromatography on Ricinus communis agglutinin and concanavalin-A. The nine variants are able to bind oestrone with the same capacity of one binding site per alpha-foetoprotein molecule. The association constants seem to vary with the sialic acid composition of the iso-alpha-foetoprotein.