Electrospray mass spectra from protein electroeluted from sodium dodecylsulfate polyacrylamide gel electrophoresis gels

Electrospray ionization/tandem mass spectrometry of proteins separated on s odium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) gels is severely limited by the requirement that the protein be completely separate d from the SDS. As shown here, the gaseous noncovalent SDS adducts of proto nated proteins thus formed can be dissociated by infrared irradiation. ESI spectra from myoglobin in SDS-containing solutions show molecular ions addu cted with up to 15 dodecyl sulfates, but ir irradiation of these ions cause s complete dissociation to expel the SDS. (C) 1999 American Society for Mas s Spectrometry.