Purine analogues are antimetabolites which mimic the structure of metabolic purines.
Examples
Examples include:
- Azathioprine is the main immunosuppressive cytotoxic substance. It is widely used in transplantations to control rejection reactions. It is nonenzymatically cleaved to 6-mercaptopurine that acts as a purine analogue and an inhibitor of DNA synthesis. By preventing the clonal expansion of lymphocytes in the induction phase of the immune response, it affects both the cell and the humoral immunity. It also successfully suppresses autoimmunity.
- Mercaptopurine
- Thioguanine is used to treat acute leukemias and induction of remissions in acute granulocytic leukemias
- Fludarabine inhibits function of multiple DNA polymerases, DNA primase, DNA ligase I and is S phase-specific (since these enzymes are highly active during DNA replication).
- Pentostatin and cladribine are adenosine analogs which are primarily used to treat Hairy cell leukemia.