Purification of human 19S thyroglobulin by gel filtration

The presence of thyroglobulin in the main peak of a Sephadex G-200 fractionation of a saline extract of human thyroid was detected by Ouchterlony double immuno-diffusion plates against rabbit antihuman thyroglobulin serum.Refiltration of thyroglobulin pooled from the first part of the main peak did not yield a pure native thyroglobulin. A pure 19S component could only be obtained by pooling the effluent corresponding to the descending slopes of the thyroglobulin peaks obtained on the one hand by filtration of the saline extracts, or on the other by refiltration of the effluent corresponding to the ascending slopes of the first filtrations.