Characterization of superoxide dismutase 1 (SOD-1) by electrospray ionization-ion mobility mass spectrometry
Article first published online: 9 JAN 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Journal of Mass Spectrometry
Volume 48, Issue 1, pages 60–67, January 2013
How to Cite
Borges-Alvarez, M., Benavente, F., Vilaseca, M., Barbosa, J. and Sanz-Nebot, V. (2013), Characterization of superoxide dismutase 1 (SOD-1) by electrospray ionization-ion mobility mass spectrometry. J. Mass Spectrom., 48: 60–67. doi: 10.1002/jms.3128
- Issue published online: 26 DEC 2012
- Article first published online: 9 JAN 2013
- Manuscript Accepted: 17 OCT 2012
- Manuscript Revised: 11 OCT 2012
- Manuscript Received: 23 JUL 2012
- Spanish Ministry of Education and Science. Grant Number: CTQ2011-27130
- ion mobility;
- mass spectrometry;
In this paper, we report nano-electrospray ionization-ion mobility mass spectrometry (nano-ESI-IM-MS) characterization of bovine superoxide dismutase (SOD-1) and human SOD-1 purified from erythrocytes. SOD-1 aggregates are characteristic of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease in humans that could be triggered by dissociation of the native dimeric enzyme (Cu2,Zn2-dimer SOD-1). In contrast to ESI-MS, nano-ESI-IM-MS allowed an extra dimension for ion separation, yielding three-way mass spectra (drift time, mass-to-charge ratio and intensity). Drift time provided valuable structural information related to ion size, which proved useful to differentiate between the dimeric and monomeric forms of SOD-1 under non denaturing conditions. In order to obtain detailed structural information, including the most relevant post-translational modifications, we evaluated several parameters of the IM method, such as sample composition (10 mM ammonium acetate, pH 7) and activation voltages (trap collision energy and cone voltage). Neutral pH and a careful selection of the most appropriate activation voltages were necessary to minimize dimer dissociation, although human enzyme resulted less prone to dissociation. Under optimum conditions, a comparison between monomer-to-dimer abundance ratios of two small sets of blood samples from healthy control and ALS patients demonstrated the presence of a higher relative abundance of Cu,Zn-monomer SOD-1 in patient samples. Copyright © 2013 John Wiley & Sons, Ltd.