MASS-SPECTROMETRY OF PROTEINS DIRECTLY FROM POLYACRYLAMIDE GELS

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