Figure 2.

Dependence of membrane proteome coverage and peptide frequency on peptide mass. For the cleavages with trypsin (KR), trypsin/cyanogen bromide (KRM), and trypsin/chymotrypsin (FYWKR) the frequency of peptide masses is depicted in the range from 0–4500 Da (Fig. 2A). For better clarity, cleavages that result in the release of a single amino acid were not counted. With these values, a length normalized value was calculated to obtain the membrane proteome coverage in relation to the peptide mass (Fig. 2B). The displayed value is per mass coverage of the total membrane proteome for the respective organism.