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Antifolates are a class of antimetabolite medications that antagonise (that is, block) the actions of folic acid (vitamin B 9). [1] Folic acid's primary function in the body is as a cofactor to various methyltransferases involved in serine, methionine, thymidine and purine biosynthesis. Consequently, antifolates inhibit cell division, DNA/RNA ...
Antifolates act primarily as inhibitors of both RNA and DNA, and are often grouped with nucleic acid inhibitors in textbooks. However, they also act indirectly as protein synthesis inhibitors (because tetrahydrofolate is also involved in the synthesis of amino acids serine and methionine), so they are sometimes considered as their own category, antimetabolites. [6]
Anti-metabolites 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. Due to their efficiency, these drugs are the most widely used cytostatics.
These carbon groups can be transferred to other molecules as part of the modification or biosynthesis of a variety of biological molecules. Folates are essential for the synthesis of DNA, the modification of DNA and RNA, the synthesis of methionine from homocysteine, and various other chemical reactions involved in cellular metabolism. [94]
PCR inhibitors are any factor which prevent the amplification of nucleic acids through the polymerase chain reaction (PCR). [1] PCR inhibition is the most common cause of amplification failure when sufficient copies of DNA are present. [2] PCR inhibitors usually affect PCR through interaction with DNA or interference with the DNA polymerase.
Because of this they have side effects such as bone marrow suppression. There is a large family of nucleoside analogue reverse transcriptase inhibitors , because DNA production by reverse transcriptase is very different from normal human DNA replication , so it is possible to design nucleoside analogues that are preferentially incorporated by ...
Dihydrofolic acid (conjugate base dihydrofolate) (DHF) is a folic acid (vitamin B 9) derivative which is converted to tetrahydrofolic acid by dihydrofolate reductase. [1] Since tetrahydrofolate is needed to make both purines and pyrimidines, which are building blocks of DNA and RNA, dihydrofolate reductase is targeted by various drugs to prevent nucleic acid synthesis.
NADP is a reducing agent in anabolic reactions like the Calvin cycle and lipid and nucleic acid syntheses. NADP exists in two forms: NADP+, the oxidized form, and NADPH, the reduced form. NADP is similar to nicotinamide adenine dinucleotide (NAD), but NADP has a phosphate group at the C-2′ position of the adenosyl.