US EPA

7440057 

Journal Article 

Effect of amino acid side-chain on fragmentation of cyclic peptide ions: differences of electrospray ionization collision-induced decomposition mass spectra of toxic heptapeptide microcystins containing ADMAdda instead of Adda 

Yuan, M; Namikoshi, M; Otsuki, A; Sivonen, K 

1998 

Yes 

European Journal of Mass Spectrometry
ISSN: 1469-0667 

4 

4 

287-298 

English 

10.1255/ejms.222 

WOS:000078599200008 

Characteristics of collision-induced decomposition (CID) spectra recorded following electrospray ionization (ESI) of toxic heptapeptide microcystins containing (2S,3S,8S,9S)-3-amino-9-acetoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (ADMAdda) have been investigated in detail and compared with those from compounds containing (2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda). A significant difference in their CID spectra was observed in the cleavage of cyclic structures in low-energy CID processes due to the effect of the amino acid side-chain on fragmentation. Microcystins containing ADMAdda produced mostly b-type ions. Fragment ions predicted on the basis of the known fragmentation of cyclic peptides and linear-peptide b-type ions, predicted by the Peptide Matching (PEPM) program, matched well with peaks in the CID spectra. A neutral loss of CH3COOH from the ADMAdda residues was observed in the CID spectra of doubly charged ions, [M + 2H]2+. The present study suggested that the CID spectra of [M + H]+ and [M + 2H]2+ ions can provide their sequence information. 

microcystins; electrospray ionization; doubly charged ion; tandem mass spectrometry; fragmentation of cyclic peptide ion