Enhancing the Sequence Informative Fragmentation through Alkali Metal Cationization of Model Cyclic Peptides by Various Dissociation Methods

摘要

1. Ring size influences the binding of metal adducts, smaller rings preferentially bind smaller cations as seen with vasopressin and sodium 2. Under high energy CID, only sodium produces product ions in vasopressin and only potassium produces product ions in somatostatin-14, likely the result of sequence and/or ring size 3. Low energy CID produces internal fragment ions with retention of the disulfide bond 4. ETD dissociates the disulfide bond and results in less product ion formation for the adduct ions when compared to the protonated species 5. No increases in sequence coverage are observed resulting from analysis of alkali adducts