Peptide mapping by CNBr fragmentation using a sodium dodecyl sulfate-polyacrylamide minigel system.

The method of peptide mapping by sodium dodecyl sulfate-gel electrophoresis following partial protein fragmentation with cyanogen bromide was adapted for a polyacrylamide minigel system. The combined use of the discontinuous gel electrophoresis system of J. P. Doucet and J. M. Trifaró [1988) Anal. Biochem. 168, 265-271) and a vertical polyacrylamide minigel system produced the following advantages over other procedures: (a) the ability to resolve cyanogen bromide cleavage fragments over a broad molecular mass range while yielding very sharp protein staining bands; (b) well-defined peptide maps are produced with as little as 2 micrograms of protein; (c) less time is required to perform fragmentation with cyanogen bromide, to equilibrate the gel slices in sodium dodecyl sulfate buffer, as well as to perform the electrophoresis; and (d) the cyanogen bromide fragmentation patterns are highly reproducible.