OBSERVATIONS CONCERNING THE HETEROGENEITY OF OVINE THYROGLOBULIN1

Abstract
Preparations of thyroglobulin have been made by salting-out techniques from the thyroid gland of a single sheep, labeled with I131 in vivo, from multiple thyroid glands labeled in vitro, and from multiple unlabeled glands. Despite electrophoretic and ultracentrifugal homogeneity, such preparations displayed evidence of heterogeneity, as assessed by their behavior during ion-exchange chromatography, ultraviolet absorption spectra, rate of turnover of I131, and amino acid content.