Compounds were classified into 17 chemical classes derived from the ClassyFire chemical hierarchy. Proteins were classified into a set of 24 target classes derived from the ChEMBL target hierarchy, after mapping each protein into a unique UniProt accession number (or set of numbers, in the case of protein complexes). Redundant entries obtained from different sources were removed, and multiple entries of each compound-protein pair were averaged to obtain a unique mean affinity value.