ECD Technology in Biological Mass Spectrometry

Electron capture dissociation (ECD) which is believed to be non-ergodic process is a new fragmentation technique used in Fourier transformation cyclotron resonance mass spectrometry and is complementary to conventional tandem mass spectrometry techniques. Its cleavage preferentially happens not only on N-C(alpha) bond but also on disulfide bonds (S-S) in polypeptides, which are normally stable to vibrational excitation. The labile post-translational modifications and non-covalent bonds often remain intact after backbone bond dissociation. ECD provides more extensive sequence coverage in polypeptides, and at higher electron energies even isoleucine and leucine are distinguishable. The combination of CAD and ECD improves protein identification and enables high-throughput de novo sequencing of proteins. An overview of the principle and mechanism of ECD as well as its application in biological mass spectrometry is given