The ligand of 1O48 binds to the SH2 domain of pp60 Src kinase, which is important in the control of cell proliferation, differentiation, motility, and adhesion. This site serves as a potential target as pp60 Src kinase has been linked to bone resorption. The ligands for 1ZP5 and 1MMQ serve as inhibitors for metalloproteases; the ligand in 1ZP5 serves as an inhibitor for N -hydroxyurea and 1MMQ's inhibitor binds to matrilysin (uterine metalloproteinase). Enzymes 1ZP5 and 1MMQ each contain two Zn 2+ and two Ca 2+ ions. In both of these metalloproteinases, over-regulation can lead to uncontrolled degradation of the extracellular matrix, which is seen in diseases including cancer, arthritis, and multiple sclerosis. The design of the ligand in 1BOZ was meant to serve as an inhibitor of Toxoplasma gondii dihydrofolate reductase and a potential antitumor agent. In addition to the inhibitor, 1BOZ also contains NADPH as a cofactor.