1P-33 PDF
Fragmentation of the peptides by electrospray ionization
The fragmentation processes of (de)protonated molecules [M±H]± of peptides M consisting of seven threonine residues, we investigated by using electrospray ionization CID-MS. In the CID of protonated molecule [M+H]+ , the formation of b and y ions via cleavage at the main chain and successive dehydration from [M+H]+ and b ions were observed. Deprotonated molecule [M-H]-, in contrast, lost all seven threonine side chains, and resulting in the generation of glycine cluster ion. The results obtained indicated that fragmentation behavior of [M+H]+ and [M-H]- for peptides consisting of threonine are considerably different.