Biological inorganic chemistry (bio-inorganic chemistry) is the study of inorganic elements as they are utilized in biology. The main focus is on metal ions, where we are interested in their interaction with biological ligands and important chemical properties they are able to exhibit and impart to an organism. These properties include ligand binding, catalysis, regulation, sensing defence and structural support. It is interdisciplinary field of chemical science (chemistry) which largely focuses on the role of metal ions in living system.