While the number of sequenced genes is increasing dramatically, the number of different protein structural families is expected to be more limited. Changes in enzymatic activity or protein interactions can dramatically modify the role of homologous proteins in different organisms or mutants. However, experimental data associated with sequences or mutations stored in databases are often limited to a short description of the enzymatic pathway, molecular interaction or phenotype associated with the changes in amino acid sequence. In the alpha/beta-hydrolases fold database ESTHER, we are experimenting with links between experimental kinetic data and sequences, mutations and protein structures. This effort will lead to the integration of pharmacological data with genome-wide databases.