Everything about Antimetabolite totally explained
An
antimetabolite is a chemical with a similar structure to a substance (a
metabolite) required for normal biochemical reactions, yet different enough to interfere with the normal functions of cells, including
cell division.
Function
Cancer treatment
Antimetabolites can be used in
cancer treatment, as they interfere with DNA production and therefore cell division and the growth of tumors. Because cancer cells spend more time dividing than other cells, inhibiting cell division harms tumor cells more than other cells.
Anti-metabolites masquerade as
purine (
azathioprine,
mercaptopurine) or
pyrimidine - which become the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during the
S phase (of the
cell cycle), stopping normal development and division.
They also affect RNA synthesis. However, because
thymidine is used in DNA but not in RNA (where
uracil is used instead), inhibition of thymidine sythesis via
thymidylate synthase selectively inhibits DNA synthesis over RNA synthesis.
Due to their efficiency, these drugs are the most widely used
cytostatics.
In the
ATC system, they're classified under
L01B.
Antibiotics
Antimetabolites may also be
antibiotics, such as
sulfanilamide drugs, which inhibit
dihydrofolate synthesis in bacteria by competing with
para-aminobenzoic acid.
Types
Main representatives of these drugs are:
Image:Folic acid structure.svg|Folic acid
Image:Methotrexate.png |Methotrexate
Image:Pemetrexed.svg|Pemetrexed
Image:Raltitrexed.svg|Raltitrexed
Trimethoprim
Pyrimethamine
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.
Image:Purine.png|Purine
Image:Mercaptopurine.svg|Mercaptopurine
Image:Tioguanine.png|Tioguanine
Image:Fludarabine phosphate.svg|Fludarabine
5-fluorouracil (5FU) which inhibits thymidylate synthase.
Floxuridine (FUDR)
Cytosine arabinoside (Cytarabine)
Image:Pyrimidin.svg|Pyrimidine
Image:Fluorouracil.svg|Fluorouracil
Image:Floxuridine.png|Floxuridine
Image:Gemcitabine.png|Gemcitabine
Further Information
Get more info on 'Antimetabolite'.
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