Structural analysis of a chelating derivative of

a melanocyte stimulating hormone by electrospray ionisation mass spectrometry

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Eur. J. Mass Spectrom. 1, 301 - 304 (1995)

Structural analysis of a chelating derivative of a melanocyte stimulating hormone by electrospray ionisation mass spectrometry

B. Devreese and J. van Beeumen^*
University of Ghent, Department of Biochemistry, Physiology andMicrobiology, 35, Ledeganckstraat, 9000 Ghent, Belgium
D. Bard
Strangeways Research Laboratory, Worts' Causeway, Cambridge, CB1 4RN, UK
F. Jacquemotte
CERIA/Meurice Institute, Department of Natural Substances, 1, Av. E. Gryzon,1070 Brussels, Belgium

ABSTRACT:

The technique of electrospray ionisation mass spectrometry has been used to study the hydrogen/deuterium exchange of bisMSHDTPA, a derivative of a-melanocyte stimulating hormone (MSH) in which two complete MSH peptide chains are covalently bound to a single molecule of diethylenetriamine pentaacetic acid (DTPA). The results show different levels of exchange between the metal chelated and the unchelated peptide. We suggest that the unchelated peptide is able to form a hydrogen-bonded structure between the carboxyl groups of DTPA and the amino nitrogen of the N'- terminal serine of MSH.

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