Reexamination of the primary structure of an antitumor protein, neocarzinostatin

The primary structure of an antitumor protein, neocarzinostatin, has been reinvestigated by conventional and gas-phase Edman degradation procedures. Sequence analyses of tryptic peptides of both S-carboxymethylated and S-aminoethylated derivatives as well as peptic peptides of the native protein revealed a revised primary structure of neocarzinostatin. The present sequence of 113 amino acid residues thus established agrees with results obtained by fast atom bombardment and gas chromatographic mass spectrometry which were published recently [B.N. Gibson, W.C. Herlihy, T.S.A. Samy, K.S. Hahm, H. Maeda, J. Meienhofer, and K. Biemann (1984) J. Biol. Chem. 259, 10801-10806]. The assignment of four intriguing asparagine/aspartic acid residues has been also achieved.