ONE-STEP MICROELECTROELUTION CONCENTRATION METHOD FOR EFFICIENT COUPLING OF SODIUM DODECYL-SULFATE GEL-ELECTROPHORESIS AND MATRIX-ASSISTED LASER-DESORPTION TIME-OF-FLIGHT MASS-SPECTROMETRY FOR PROTEIN-ANALYSIS

The coupling of the widely used separation technique of conventional s odium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) wit h the mass accuracy measurement capability of mass spectrometry (MS) p rovides a very powerful analytical technique. However, at present, the re is no simple, definitive method for coupling the two methods. Typic ally, separated proteins are extracted from the gel, either as the nat ive protein or as a peptide mixture after in-gel proteolytic digestion , and then analyzed by mass spectrometry. However, the various extract ion techniques described previously have been labor intensive and requ ire a large number of steps. The mass spectrometry analysis of very lo w concentrations of in vivo derived proteins requires minimum sample h andling and on-line concentration. Therefore, we have developed an eff icient microelectroelution technique that is applied in a single step manner and contains an on-line concentration device. Initial results f rom this system have shown a high efficiency of analyte elution from t he gel and a simple, robust technique for the coupling of SDS-containi ng gels with MALDI-TOF-MS analysis and a capability of analyzing prote ins at the subpicomole level. (C) 1998 American Society for Mass Spect rometry.