Fig. 3.

The MALDI-TOF mass spectra of the fragments from the subunit CcoN of cytochrome cbb₃ after cleavage with endoproteinase Asp-N (black trace) and after double digestion with both endoproteinase Asp-N and trypsin (red trace). The assignments of the subunit CcoN fragments as average (>3,300 Da) or monoisotopic (<3,300 Da) masses are indicated in the spectrum and the respective amino acid numbering are shown in brackets. The most important parts of the spectra are shown as Insets: the 11,715-Da fragment produced by endoproteinase Asp-N cleavage (Left), the 10,511-Da region before and after the trypsin digestion (Center), and the 1,241-Da region after the double digestion (Right).