MASS-SPECTROMETRIC INVESTIGATIONS ON CONUS PEPTIDES

Molecular masses and primary structure determination of Conus peptides , such as alpha-, mu- and omega-conotoxins, conantokins and conopressi ns, were accurately measured by state-of-the-art mass spectrometric te chniques using only 1-2 pmole quantities. Soft ionization of Conus pep tides under electrospray, matrix-assisted laser desorption and continu ous flow frit-FAB conditions produced their corresponding singly and m ultiply charged molecular ions which can be detected by mass spectrome tric analysis. The molecular masses of Conus peptides were obtained by the deconvolution of the multiply charged pseudo-molecular ions. Mixt ure analysis without chromatographic separation can be accomplished by this approach. The ions formed during collision-induced dissociation of either singly or multiply charged ions of any reduced and derivatiz ed peptide provided the corresponding sequences of the amino acids. Pr eliminary investigations indicate that the developed techniques and pr ocedures could be applied in order to characterize the peptides presen t in unknown Conus venoms from the Bay of Bengal region.