Open AccessObservation of pronounced b•,y cleavages in the electron capture dissociation mass spectrometry of polyamidoamine (PAMAM) dendrimer ions with amide functionalities
Author(s) -
Sun Young Lee,
Sang Yun Han,
Tae Geol Lee,
Gyusung Chung,
Duckhwan Lee,
Han Bin Oh
Publication year - 2006
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2005.12.004
Subject(s) - chemistry , dendrimer , electron capture dissociation , amide , dissociation (chemistry) , mass spectrometry , fragmentation (computing) , protonation , solvation , intramolecular force , moiety , ion , tandem mass spectrometry , photochemistry , stereochemistry , organic chemistry , chromatography , computer science , operating system
We report the electron capture dissociation (ECD) mass spectrometry of the third generation polyamidoamine (PAMAM) dendrimer that contains amide functionalities. The dendrimer was chosen because it offers a unique opportunity to understand the ECD behavior of the amide functionality in a framework other than peptides/proteins. In this study, PAMAM ECD was found to exhibit a fragmentation pattern strikingly different from that of ordinary peptide/protein ECD. Specifically, ECD of multiply protonated PAMAM ions gave rise to significant b(*),y cleavages as well as S,E dissociations but, unexpectedly, only minor c,z(*) fragmentations are observed. In an effort to account for the unexpectedly different fragmentation pattern, a comparative ECD experiment on the poly(propylene imine) dendrimer in which the amide bond moiety is not available and density functional theory calculations (B3LYP/6-311 + G(d)) investigations on the model system of a charge-solvated single-repeat unit were carried out. On the basis of these results, we discuss here possible implications of intramolecular charge-solvation, energy barriers in dissociation reactions, and macromolecular properties of the dendritic molecule for understanding the reaction pathway of PAMAM ECD.