The current set of descriptors implemented in the last version of MAYA are Molecular ACCes System (MACCS) keys (166-bits) , extended connectivity fingerprints (ECFP) of diameter 4 and 6 (ECFP4, ECFP6) (2048-bits) ; six continuous properties of pharmaceutical relevance, and biological descriptors. The properties of pharmaceutical relevance are molecular weight (MW), logP (LogP), topological polar surface area (TPSA), number of hydrogen bond donors (HBD), number of hydrogen bond acceptors (HBA), and number of rotatable bonds (RB), both fingerprints and molecular descriptors are calculated using the RDkit library. The bioactivity signatures offer a new opportunity to integrate bioactivity knowledge into similarity calculations, including for compounds that are not annotated with experimental data. To achieve a more comprehensive approach we have implemented several signatures, such as mechanisms of action, binding, small molecule roles, small molecule pathways, diseases and toxicology, and drug-drug interactions. These are integrated into MAYA based on the performance accuracy of the signatures in reproducing the original information. Further details of the biological descriptors included in the current version of MAYA are described elsewhere .