Fig. 4.

Schematic example of the process protein abundance normalization. A) Schematic of a simplified case of normalization according to scenario A (see also Fig. 3A). First, the fraction with the highest value is identified, separately for heavy and light samples. Next, the value of each fraction is divided by this maximum value within each labelling state. This means that, for Protein A, there will be a value of 1 present at least in one fraction for the heavy sample and at least in one fraction for light sample. B) Schematic of a simplified case of normalization according to scenario B (see also Fig. 3B). First, the fraction with the highest value across both labelling states is identified. Next, the value of each fraction is divided by this maximum value. This means that, for Protein A, there will be a value of 1 present at least in one fraction in at least one of the heavy or light samples.