title: Post-translation processing of neurohormonal peptide precursors in a human medullary thyroid carcinoma.
abstract: Determination of the Primary structures of peptides isolated from a human medullary thyroid carcinoma has provided insight into the pathways of post-translational processing of prohormones in the tumour cells. Cleavage of the signal peptide in preprocalcitonin occurs at the Ala25-Ala26 bond. The prohormone is further processed at the site of multiple basic residues to generate procalcitonin-(1-57)-peptide, procalcitonin-(60-91)-peptide (calcitonin), procalcitonin(60-116)-peptide (a C-terminally extended form of calcitonin) and procalcitonin-(96-116)-peptide (Katacalcin). CGRP-I but not CGRP-II, was isolated from the tumour together with a high-Mr form that may represent the unprocessed prohormone. Progastrin-releasing peptide was processed to a mixture of GRP-(1-27)-peptide and GRP-(18-27)-peptide, the latter component arising from proteolytic cleavage at the site of a single arginyl residue.
authors.affiliation: Klinische Arbeitsgruppe für Gastrointestinale Endokrinologie der Max-Planck-Gesellschaft, Universität Göttingen, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Conlon
mesh_terms: D002116:Calcitonin / Q000235:genetics / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics / Q000378:metabolism; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D019886:Gastrin-Releasing Peptide; D015870:Gene Expression; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000235:genetics*; D011863:Radioimmunoassay; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism; D014665:Vasodilator Agents / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D010455:Peptides; D011498:Protein Precursors; D014665:Vasodilator Agents; D019886:Gastrin-Releasing Peptide; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide