Related Experiment Video
Updated: Jun 13, 2026

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids
Published on: February 21, 2018
A unique approach to the mobile proton model: influence of charge distribution on peptide fragmentation
Feng Sun1, Rutao Liu, Wansong Zong
1School of Environmental Science and Engineering, Shandong University, 27 Shanda South Road, Jinan 250100, PR China.
Abstract:
The cleavage processes of protonated peptides in mass spectrometry, described in the mobile proton model, are charge-directed and depend on the charge distribution around the cleavage sites. Previous studies experimentally verified the mobile proton model by changing peptide sequences. In this study, oxidation was applied to change the charge distribution of peptides, but the sequence was retained. Tandem mass spectrometry (MS/MS) and quantum chemical calculations at the B3LYP/6-31G(d) level were used to test the validity of the mobile proton model. The results showed prominent differences of peptide fragmentation efficiency caused by the charge distribution produced by various oxidation levels. Fragmentation efficiency curves coupled with the relative intensities of the fragments indicated that the cleavage of the peptide Ala-Arg-Arg-Ala (ARRA) became more and more difficult as O atoms were added. The relative charge ratios between C and N atoms in the amide bonds decreased with the increase of oxidation extent, suggesting that oxidation resulted in protons moving away from the amide bonds. The combined methods proposed here provide a unique approach to substantiate and refine the mobile proton model for peptide fragmentation.
More Related Videos
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
16:40T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Published on: July 31, 2010
Related Concept Videos
Mass Spectrometry: Molecular Fragmentation Overview
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
Peptide Identification Using Tandem Mass Spectrometry
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides’ amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of...
Mass Spectrometry of Amines
Mass Spectrometry: Carboxylic Acid, Ester, and Amide Fragmentation
For example, the fragmentation of...
Mass Spectrometry: Amine Fragmentation
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)