Figure 5 shows an example result of applying Algorithm 2 for differentially phosphorylating a set of peptides on the array “A-1”. The replicate, parameter Y, was as shown in Figure 1. Differentially phosphorylated peptides in Figure 5 are depicted in red. Again background-correct intensity values are plotted. It should be noted that although we set the number of candidate peptides for phosphorylation to be 30, i.e., the length of phosphorylated vector in Algorithm 2, the number of differentially phosphorylated peptides is less than or equal to 30. This can happen because of an attempt to (de)phosphorylate a peptide that is highly (de)phosphorylated. This can lead to fewer differentially phosphorylated peptides than specified by nd. Scatter plots of original versus artificially phosphorylated replicate array pairs for three template arrays other than “A-1” in the input dataset are shown in Figures S7–S9 in Supplementary Materials.