engleski

Mass spectrometric characterization of Amadori compounds related to the opioid peptide morphiceptin

The high-energy collision-induced dissociation (CID) spectra of synthesized Amadori compounds, related to the exogenous opioid peptide morphiceptin, have been investigated. The spectra of [M + H]+ ions of protected, partially protected and unprotected Amadori compounds exhibit mainly A- and Y″-type sequence ions. The protected compounds show peaks corresponding to the elimination of a C3H6O molecule, characteristic of a protecting isopropylidene group at the saccharide moiety. The position of the isopropylidene group in the partially protected Amadori compound has been derived from the CID spectrum of its [M + Na]+ ion. A two-bond cross-ring cleavage reaction generates an ion at m/z 656, corresponding to the loss of a 90 Da neutral (C3H6O3), and must originate from the C2-C3 isopropylidene- protected Amadori compound. The most intense ions in the CID spectrum of the [M + H]+ ion of the unprotected Amadori compound arise from losses of water molecules. Comparison of the CID spectra of the [M + H]+ ions of Amadori compounds with that for the parent peptide morphiceptin revealed a preferential A1-ion formation for Amadori compounds.

mass spectrometry ; Amadori ; morphiceptin ; opioid ; glycation

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