- dihydrofolate reductase
- An enzyme reversibly oxidizing tetrahydrofolate to 7,8-dihydrofolate with NADP+. A crucial enzyme in one-carbon metabolism; used as a marker of drug resistance to methotrexate. SYN: 5,6,7,8-tetrahydrofolate dehydrogenase.
* * *di·hy·dro·fo·late reductase -'fō-.lāt- n an enzyme that catalyzes the reduction of a folate having one of its rings with two double bonds and two attached hydrogen atoms into the dihydro form differing only in having one double bond and four hydrogen atoms in the same ring, that is essential for DNA and protein synthesis, and that is targeted by some anticancer drugs (as methotrexate) in order to inhibit its positive effect on tumor cell growth and reproduction
* * *di·hy·dro·fo·late re·duc·tase (di-hi″dro-foґlāt re-dukґtās) [EC 188.8.131.52] an enzyme of the oxidoreductase class that catalyzes the reduction of dihydrofolate to tetrahydrofolate, using NADPH as an electron donor. The reaction produces reduced folate for amino acid metabolism, purine ring synthesis, and the formation of deoxythymidine monophosphate. Methotrexate and other folic acid antagonists used as chemotherapeutic drugs act by inhibiting this enzyme. Deficiency of the enzyme may be a cause of megaloblastic anemia responsive to therapy with reduced forms of folic acid. Abbreviated DHFR.
Medical dictionary. 2011.