Finally, we computed the predicted reactivity for all the sequences generated from the positive and negative clusters. The final list was formed by: i) the 1100 peptides with the highest predicted reactivity generated from the positive clusters, ii) the 1100 with lowest predicted reactivity from the negative clusters and iii) 1100 peptides randomly selected from the uncertain clusters. As shown in Figure 4 , the distributions of the predicted reactivity clearly separate the peptides coming from the positive clusters and the negative ones. This demonstrates the validity of the strategy adopted to generate new peptides.