N Moreover in subset B all the features derived from global alignment have been removed, suggesting, as expected, that the reactivity depends on a small portion of the peptide, which probably corresponds to the binding site (information retrieved by local alignment). Also in the case of subset C, two out of the three remaining alignment-based features have been derived from local alignment. N As the amino acid frequencies are concerned, the attributes associated to the presence of X, B and J are present in both subsets B and C, since few sequences contain such residues. The features related to Alanine and Isoleucine have been removed only from subset C.