Journal
ANALYTICAL CHEMISTRY
Volume 77, Issue 1, Pages 172-177Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ac0489115
Keywords
-
Categories
Ask authors/readers for more resources
In-source decay (ISD) in matrix-assisted laser desorption/ionization (MALDI) shares some similarities with the novel fragmentation technique electron capture dissociation (ECD). In both reactions, the otherwise strong N-C-alpha bond is cleaved, forming fragment ions of the c and z types, while labile posttranslational modifications are preserved. Therefore, it is tempting to assume that ISD and ECD have some mechanistic aspects in common. Because electrons are present in the MALDI plume, we investigated the previously suggested possibility that ISD is a variation of ECD. However, experiments with peptides with only one site for efficient protonation revealed that ISD is not caused by electron capture. Instead, ICD seems to be induced by hydrogen atoms generated by a photochemical reaction of the matrix. We provide evidence for this reaction by hydrogen/deuterium exchange experiments with peptides containing a minimal number of exchangeable hydrogen atoms. The hydrogen atom model in ECD is indirectly supported by the proposed fragmentation mechanism for ISD, because our data suggest that hydrogen radicals can induce fragmentation by cleavage of the N-C-alpha bond, independent from their origin.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available