Microsequencing evidence for the maturation of human proopiomelanocortin into an 18 amino acid beta-melanocyte stimulating hormone [h beta MSH(5-22)] in nonpituitary tissue.

Abstract

Sixty pmoles of a material with molecular size, immunological, and RP-HPLC characteristics identical to that of h beta MSH(5-22) were purified from a bronchial carcinoid tumor responsible for the ectopic ACTH syndrome. The first 16 cycles of microsequencing revealed the following sequence: Asp-Glu-Gly-Pro-Tyr-Arg-Met-Glu-X-Phe-Arg-Trp-Gly-X-Pro- Pro-, identical to the first 16 amino acids of h beta MSH(5-22). Since this material was recognized by an antibody which requires the free COOH-terminal Asp22 residue, it can be assumed that it is indeed h beta MSH(5-22). We also show that neither the 5 N acetic acid nor the 1 N HCl extraction procedure artefactually generated h beta MSH-like material in normal or tumoral human pituitaries and in nonpituitary tumors. We conclude that h beta MSH(5-22) is a normal maturation product of proopiomelanocortin in the human nonpituitary tissues which express its gene, including the hypothalamus and ACTH-secreting tumors.

• Authors: X Bertagna, N Seidah, J F Massias, F Lenne, J P Luton, F Girard, M Chretien
• Journal: Peptides (Peptides) 1989 Jan-Feb Vol. 10 Issue 1 Pg. 83-7 ISSN: 0196-9781 [Print] United States
• PMID: 2748427 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Peptide Fragments
• MSH, beta, (5-22)
• Pro-Opiomelanocortin
• Melanocyte-Stimulating Hormones

Topics

• Amino Acid Sequence
• Carcinoma, Bronchogenic (analysis)
• Chromatography, Gel
• Chromatography, High Pressure Liquid
• Humans
• Lung Neoplasms (analysis)
• Melanocyte-Stimulating Hormones
• Molecular Sequence Data
• Peptide Fragments
• Pituitary Neoplasms (analysis)
• Pro-Opiomelanocortin (isolation & purification)
• Radioimmunoassay