Charge carrier field emission determines the number of charges on native state proteins in electrospray ionization.

ABSTRACT: Although multiple charging in electrospray ionization (ESI) is essential to protein mass spectrometry, the underlying mechanism of multiple charging has not been explicated. Here, we present a new theory to describe ESI of native-state proteins and predict the number of excess charges on proteins in ESI. The theory proposes that proteins are ionized as charged residues in ESI, as they retain residual excess charges after solvent evaporation and do not desorb from charged ESI droplets. However, their charge state is not determined by the Rayleigh limit of a droplet of similar size to the protein; rather, their final charge state is determined by the electric field-induced emission of small charged solute ions and clusters from protein-containing ESI droplets. This theory predicts that the n

SUBMITTER: Hogan CJ 

PROVIDER: S-EPMC2638767 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature