Childhood acute lymphoblastic Tetrahydrofolic acid (THF, FH-4) is required as a methyl donor in the conversion of dUMP to thymidine and in the synthesis of the purine ring. Sulfonamide or sulpha drugs are generally known as folate synthesis inhibitors because they inhibit the synthesis of folic acid, an important precursor for the synthesis of nucleic acids in pathogenic bacteria.They are antimetabolites; and antibiotics in this category include pyrimethamine, trimethoprim, sulphamethoxazole and sulphamethoxazole-trimethoprim. Mode of action of site-directed irreversible folate analogue inhibitors of thymidylate synthase. Dihydrofolate reductase (DHFR) of the parasite Trypanosoma cruzi (T. cruzi) is a potential target for developing drugs to treat Chagas' disease. Consequently, antifolates inhibit cell division, DNA/RNA synthesis and repair and protein synthesis. Sulfamethoxazole inhibits the bacterial enzyme which converts PABA into folic acid. Some such as proguanil, pyrimethamine and trimethoprim selectively inhibit folate's actions in microbial organisms such as bacteria, protozoa a… folic acid deficiency, the catabolism of FIGLU is impaired and glutamate cannot Vit generated from formiminoglutamate; therefore, formiminoglutamate accumulates in the inhibitor and is excreted in. The first antifolate drug, aminopterin, is a folic acid analog (4-aminofolic acid) that inhibits dihydrofolate reductase, preventing the reduction of folic acid and dihydrofolic acid to THF. Term sulfonamide is employed herein as generic name of. * Monotherapy or Combination of Trimethoprim and pyrimethamine (potent folic acid synthesis blockers) can result in folic acid deficiency * Folic acid deficiency in turn often causes hemolytic disturbances including megaloblastic anemia, granulocytopenia, leukopenia, and thrombocytopenia * Side effects can be avoided by giving folic acid supplementation Folic Acid. The molecular connection between the pathways is discussed. We have undertaken a detailed structure-activity study of this enzyme. MTX is a folic acid analog that interferes with the synthesis of DNA and RNA by inhibiting the enzyme dihydrofolate reductase and therefore the production of reduced folate analogs that are required for de novo synthesis of DNA and RNA precursors, such as purines and pyrimidines. Classification: . Folic Acid Synthesis Inhibitors