Transfer of SDS-proteins from gel electrophoretic zones into mass spectrometry, using electroelution of the band into buffer without sectioning of the gel

Five SDS-proteins, ranging in molecular weight from 14 to 66 kDa, were dete cted without covalent fluorescent labeling by the automated gel electrophor esis apparatus with intermittent fluorescence scanning (HPGE apparatus, Lab Intelligence) during electrophoresis in barbiturate buffer in the presence of Cascade Blue. The SDS-proteins were electroeluted from the gel into 220 mu l of buffer by a modification of the procedure of Gombocz and Cortez [1] . The electroeluate was freed of SDS, ultrafiltered and subjected to MALDI- TOF mass spectrometry. The masses of the five native proteins were found to be maintained after electrophoresis and electroelution in the presence of the potential contaminants SDS, barbituric acid and Cascade Blue. The proce dure of protein transfer from SDS-PAGE into mass spectrometry, without exci sion of bands, gel maceration and protein recovery by diffusion, therefore is shown to be suitable for the identification by mass of intact proteins d erived from gel electrophoretic bands. (C) 2000 Elsevier Science BN. All ri ghts reserved.