Antimetabolite

A substance bearing a close structural resemblance to one required for normal physiological functioning, and exerting its effect by interfering with the utilization of the essential metabolite.

It competes with, replaces, or antagonizes a particular metabolite; for example, ethionine is an antimetabolite of methionine.

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Wikipedia says The presence of antimetabolites can have toxic effects on cells, such as halting cell growth and cell division, so these compounds are used as chemotherapy for cancer.[2]

and Anti-metabolites masquerade as a purine (azathioprine, mercaptopurine) or a pyrimidine, chemicals that 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.[4]

Antimetabolite Also found in: Dictionary, Thesaurus, Medical, Encyclopedia. Related to Antimetabolite: methotrexate The drug methotrexate (right) is an antimetabolite that interferes with the metabolism of folic acid (left).

An antimetabolite is a chemical that inhibits the use of a metabolite, which is another chemical that is part of normal metabolism.[1] Such substances are often similar in structure to the metabolite that they interfere with, such as the antifolates that interfere with the use of folic acid. The presence of antimetabolites can have toxic effects on cells, such as halting cell growth and cell division, so these compounds are used as chemotherapy for cancer.[2]

Function Cancer treatment

Antimetabolites can be used in cancer treatment,[3] 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 a purine (azathioprine, mercaptopurine) or a pyrimidine, chemicals that 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.[4]

They also affect RNA synthesis. However, because thymidine is used in DNA but not in RNA (where uracil is used instead), inhibition of thymidine synthesis via thymidylate synthase selectively inhibits DNA synthesis over RNA synthesis.

Antimetabolites may also be antibiotics, such as sulfanilamide drugs, which inhibit dihydrofolate synthesis in bacteria by competing with para-aminobenzoic acid.[5] Types

Main categories of these drugs include:

  base analogs (altered nucleobases):
      purine analogues
      pyrimidine analogues
  nucleoside analogues:
      nucleosides with altered nucleobases
      nucleosides with altered sugar component (e.g. Cytarabine, ...)
  nucleotide analogues
  antifolates