1) Chelating agent 
Pendetide (GYK-DTPA) is a chelating agent. It consists of pentetic acid (DTPA) linked to the tripeptide glycine (G) – L-tyrosine (Y) – L-lysine (K). ==Use== The following monoclonal antibodies are linked to pendetide to chelate a radionuclide, indium-111. The antibodies selectively bind to certain tumour cells, and the radioactivity is then us...