Effects of cations on protein and peptide charging in electrospray ionization from aqueous solutions.

ABSTRACT: The effects of eight different cations with ionic radii between 69 and 337 pm on the charging of peptides and proteins with electrospray ionization from aqueous acetate salt solutions are reported. Significant adduction occurs for all cations except NH4(+), and the average protein charge is lower when formed from solutions containing salts compared with solutions without salts added. Circular dichroism and ion mobility results show the protein conformations are different in pure water compared with salt solutions, which likely affects the extent of charging. The average charge of protein and peptide ions formed from solutions with Li(+) and Cs(+), which have Gibbs solvation free energies (GSFEs) that differ by 225 kJ/mol, is similar. Lower charge states are typically formed from solutions

SUBMITTER: Susa AC 

PROVIDER: S-EPMC4051497 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature