Purine analogue

Purine analoguesareantimetabolitesthat mimic the structure of metabolicpurines.

Examples

• Nucleobase analogues
  • Thiopurinessuch as thioguanine are used to treat acute leukemias and remissions in acute granulocytic leukemias.
    • Azathioprineis the main immunosuppressive cytotoxic substance. A prodrug, it is widely used in transplantation to control rejection reactions. It is nonenzymatically cleaved tomercaptopurine,a purine analogue that inhibits DNA synthesis. By preventing the clonal expansion of lymphocytes in the induction phase of the immune response, it affects bothcell immunityandhumoral immunity.It also successfully suppressesautoimmunity.
    • Mercaptopurine
    • Thioguanine
• Nucleoside analogues
  • Clofarabine
  • Pentostatinandcladribineare adenosine analogs that are used primarily to treathairy cell leukemia.
• Nucleotide analogues
  • Fludarabineinhibits multipleDNA polymerases,DNA primase,andDNA ligase I,and isS phase-specific (since these enzymes are highly active during DNA replication).

• 
  Purine
• 
  Mercaptopurine
• 
  Thioguanine
• 
  Fludarabine

Medical uses

Purine antimetabolites are commonly used to treat cancer by interfering with DNA replication.