Chemical Characterization of Ectopic ACTH Purified From a Malignant Thymic Carcinoid Tumor

Abstract

ACTH was purified from a thymic tumor associated with ectopic ACTH production by gel filtration and ion exchange chromatography. Amino acid composition and C- and N-terminal analyses indicated that this tumor ACTH was comprised of the 2–38 sequence of authentic pituitary ACTH. Theobservations suggest that the mode of cleavage of this tumor ACTH from its precursor is different from that of pituitary ACTH.