1. Observation of Pronounced b•,y Cleavages in the Electron Capture Dissociation Mass Spectrometry of Polyamidoamine (PAMAM) Dendrimer Ions with Amide Functionalities
- Author
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Lee, Sunyoung, Han, Sang Yun, Lee, Tae Geol, Chung, Gyusung, Lee, Duckhwan, and Oh, Han Bin
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AMIDES , *MACROMOLECULES , *ELECTRON capture , *MASS spectrometry - Abstract
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. [Copyright &y& Elsevier]
- Published
- 2006
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