Purine analogues are

antimetabolite An antimetabolite is a chemical that inhibits the use of a metabolite, which is another chemical that is part of normal metabolism. Such substances are often similar in structure to the metabolite that they interfere with, such as the antifolate ...

s that mimic the structure of metabolic

purine Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines ...

Examples

* Nucleobase analogues ** Thiopurines such as thioguanine are used to treat acute leukemias and remissions in acute granulocytic leukemias. ***

Azathioprine Azathioprine (AZA), sold under the brand name Imuran, among others, is an immunosuppressive medication. It is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and systemic lupus erythematosus, ...

is the main immunosuppressive cytotoxic substance. A prodrug, it is widely used in transplantation to control rejection reactions. It is nonenzymatically cleaved to

mercaptopurine Mercaptopurine (6-MP), sold under the brand name Purinethol among others, is a medication used for cancer and autoimmune diseases. Specifically it is used to treat acute lymphocytic leukemia (ALL), acute promyelocytic leukemia (APL), Crohn's dis ...

, a purine analogue that inhibits DNA synthesis. By preventing the clonal expansion of lymphocytes in the induction phase of the immune response, it affects both

cell immunity Cell-mediated immunity or cellular immunity is an immune response that does not involve antibody, antibodies. Rather, cell-mediated immunity is the activation of phagocytes, antigen-specific Cytotoxic T cell, cytotoxic T-lymphocytes, and the rel ...

and humoral immunity. It also successfully suppresses

autoimmunity In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". ...

. ***

Mercaptopurine Mercaptopurine (6-MP), sold under the brand name Purinethol among others, is a medication used for cancer and autoimmune diseases. Specifically it is used to treat acute lymphocytic leukemia (ALL), acute promyelocytic leukemia (APL), Crohn's dis ...

***

Thioguanine Tioguanine, also known as thioguanine or 6-thioguanine (6-TG) is a medication used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), and chronic myeloid leukemia (CML). Long-term use is not recommended. It is given by mouth. ...

Nucleoside analogue Nucleoside analogues are nucleosides which contain a nucleic acid analogue and a sugar. Nucleotide analogs are nucleotides which contain a nucleic acid analogue, a sugar, and a phosphate group with one to three phosphates. Nucleoside and nucl ...

s **

Clofarabine Clofarabine is a purine nucleoside antimetabolite marketed in the United States and Canada as Clolar. In Europe and Australia/New Zealand the product is marketed under the name Evoltra. It is FDA-approved for treating relapsed or refractory acute ...

** Pentostatin and

cladribine Cladribine, sold under the brand name Leustatin, among others, is a medication used to treat hairy cell leukemia (leukemic reticuloendotheliosis) and B-cell chronic lymphocytic leukemia. Cladribine, sold under the brand name Mavenclad, is indicat ...

are adenosine analogs that are used primarily to treat

hairy cell leukemia Hairy cell leukemia is an uncommon hematological malignancy characterized by an accumulation of abnormal B lymphocytes. It is usually classified as a subtype of chronic lymphocytic leukemia (CLL). Hairy cell leukemia makes up about 2% of all leu ...

. *Nucleotide analogues ** Fludarabine inhibits multiple

DNA polymerase A DNA polymerase is a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphates, the molecular precursors of DNA. These enzymes are essential for DNA replication and usually work in groups to create ...

s, DNA primase, and DNA ligase I, and is S phase-specific (since these enzymes are highly active during DNA replication). File:Purine.png,

Purine Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines ...

File:Mercaptopurine.svg,

File:Tioguanine.svg,

File:Fludarabine phosphate.svg, Fludarabine

Medical uses

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

References

Antimetabolites * {{biochem-stub