Internal sequence analysis of proteins eluted from polyacrylamide gels.

We have developed an elution-digestion-sequencing (EDS) method, which yields the internal amino acid sequence of partially purified proteins. The overall yield for the method was greater than 60%. The method yielded peptide peaks that could be sequenced on HPLC for all tested proteins with masses from 45 to 200.10(3) and yielded internal amino acid sequence information when as little as 10 pmol of partially purified protein was used as the starting material. The EDS method was extremely reliable and gave sequence information for each of 25 proteins tested, including high-molecular-mass proteins (M(r) > 100.10(3)) that were difficult to sequence by other methods.