Mass spectrometry of proteins directly from polyacrylamide gels

The direct combination of thin-layer gel electrophoresis and matrix-assisted laser desorption/ionization mass spectrometry has been demonstrates with good sensitivity and mass accuracy, offering potential advantages in speed and reduced complexity. Mass spectra a have been obtained from isoelectric focusing sodium dodecyl sulfate, and native gels with as little as 660 fmol of alpha- and beta-chain bovine hemoglobin and 1 pmol of horse heart myoglobin loaded. CNBr digests were performed in situ, and the products were probed in-gel, Noncovalent complexes such as multimeric protein systems, enzyme inhibitor complexes, and protein-ligand complexes can also be characterized when gel electrophoresis is run under nondenaturing conditions. This approach shows promise for simplifying the interface between gel electrophoresis and mass spectrometry.