Conversely, the refined set was constructed by applying a relatively stringent set of rules to guarantee the quality of the samples. The latest version of the refined set (v.2020, available at ) is composed of 5,316 protein-ligand complexes with binding affinity data (only Ki and Kd with exact values provided) manually collected from their source 32,41,42 . The refined set was constructed according to several criteria concerning (i) the quality of the structures, (ii) the binding affinity data, and (iii) the nature of the complex. Binding affinities in the refined set comprise a wide diversity of values, ranging from 1.2 pM (1.2×10-12 M) to 10 mM (1.0×10-3 M). In addition to the pKi/pKd values initially provided, we converted the binding constants to energy units in kcal.mol-1 to ease the development of machine-learning models aiming to predict the absolute free energy of binding.