ARE THE ELECTROSPRAY MASS-SPECTRA OF PROTEINS RELATED TO THEIR AQUEOUS-SOLUTION CHEMISTRY

The shape of the profile described by the relative abundances of multiply charged ions of proteins in the electrospray mass spectrum can be described by means of one or more Gaussian functions. An aqueous solution equilibrium model of the distribution of multiply charged ions of equine cytochrome c and myoglobin has been shown to match qualitatively the shape of the distribution of these ions in an electrospray mass spectrum. Monotonic functions such as the quadrupole mass spectrometric transmission efficiency may alter the centroid of the profile, but the shape of the ion abundance pattern appears to be controlled by the aqueous solution chemistry of the proteins.