MOLECULAR-FORMS OF KATACALCIN, CALCITONIN GENE-RELATED PEPTIDE AND GASTRIN-RELEASING PEPTIDE, IN A HUMAN MEDULLARY-THYROID CARCINOMA

  • 1 May 1988
    • journal article
    • research article
    • Vol. 48  (9) , 2412-2416
Abstract
Peptides synthesized by a human medullary thyroid carcinoma were purified to homogeneity by reverse-phase high performance liquid chromatography and structurally characteized by determination of amino acid composition, amino acid sequence, and fast atom bombardment mass spectra. The katacalcin-related material in the tumor extract was heterogeneous. Katacalcin (1-21) represented the predominant molecular form but metabolites, identified as katacalcin (1-20), (1-19), (1-15) and (1-13), were also identified in high concentration. Calcitonin gene-related peptide-I was isolated from the tumor but calcitonin gene-related peptide-II was absent. A minor component of calcitonin gene-related peptide-like immunoreactivity was of higher molecular weight and may represent an incompletely processed form of the prohormone. Gastrin-releasing peptide (1-27) and gastrin-releasing peptide (18-27) (neuromedin C) were isolated from the tumor but gastrin-releasing peptide (14-27)0 and bombesin were absent.