This invention relates to processes for identifying peptide and polypeptide ligands for a binding partner by using principal component analysis of amino acids to derive vectors describing amino acid subsets corresponding to peptides with known binding affinities and then using this information in a neural network modeling process to derive binding prediction equations. These binding prediction equations are then used in the analysis of subsets of amino acids from a target source to identify peptides or polypeptides ligands in the target source that have affinity for a binding partner.