Dye-affinity purification of transthyretin from an unexploited by-product of human plasma chromatographic fractionation.

Dye-affinity chromatography of human plasma transthyretin on Remazol Yellow GGL-Sepharose from an unexploited by-product of chromatographic fractionation of plasma was optimized for large-scale preparation of a therapeutic product. With this system, transthyretin is only weakly bound to the gel. The residence time on gel and the transthyretin level in the by-product were observed to have no influence on the binding capacity of gel, and the optimum amount of transthyretin to be applied to the gel was found to be 1 g/l of gel. The adsorbent can be used more than ten times. The procedure resulted in the isolation, with a 30% yield with respect to plasma, of an 80% pure protein, which retained its thyroxine-binding capacity. Although the purity is acceptable for substitutive therapy, it can be improved further with a second chromatography on Cibacron Blue-Sepharose.