It is classified as a purine analog, which is a type of antimetabolite. It mimics the nucleoside adenosine and thus inhibits the enzyme adenosine deaminase, interfering with the cell's ability to process DNA. Cancer cells generally divide more often than healthy cells; DNA is highly involved in cell division (mitosis) and drugs which target DNA-related processes are therefore more toxic to cancer cells than healthy cells.
Pentostatin
Vasopressin 
Vasopressin
Bryostatin
Endrin
Gluten exorphin
Immunoevasin
Tetanospasmin