Vitae [online]. ISSN Dihydrofolate reductase is an enzyme involved in the production of pyrimidinic base timidin, a structural component of DNA, therefore whatever substance that inhibit this enzyme inhibit the DNA synthesis as a consequence and it can be potentially useful as a treatment of several types of cancer like lymphoblastic leukemias. In this work we determinate the inhibition grade that the ethanol extracts from Colombian marine sponges: Svenzea zeai , Amphimedon compressa , Ircinia campana , Aplysina archeri , Xestospongia proxima y Xestospongia muta , over the human purified enzyme dihydrofolate reductase. The results shown that most of marine sponge extracts inhibite the enzyme. All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License.
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It catalyzes the reduction of dihydrofolic acid to tetrahydrofolic acid folate. The folate is a form of the essential vitamin B9. Both enzymes participate in the biosynthesis of pyrimidine.
DHFR is a ubiquitous enzyme found in all organisms. The primary physiological role of DHFR is maintenance of the intracellular levels of tetrahydrofolate, a precursor of cofactors required for the biosynthesis of purines, pyrimidines, and several amino acids. The enzyme, which is the sole source of tetrahydrofolate catalyzes the reduction of DHF magenta to 5,6,7,8-tetrahydrofolate THF by stereospecific hydride transfer from the blue cofactor to the C6 atom of the pterin ring with concomitant protonation at N5.
The active site cleft divides the protein into two structural subdomains: the red and the green. The adenosine binding subdomain is the smaller of the two subdomains and provides the binding site for the adenosine moiety of the cofactor. Hinge bending motions about Lys38 and Val88 allow the adenosine binding domain to move relative to the major domain upon binding of various ligands, resulting in closure of the active site cleft.
Antifolate inhibitors like Methotrexate MTX which is very similar to folic acid are used in cancer therapy. A movie depicting the conformational changes of DHFR during one turnover of substrate has been constructed by M. Sawaya and J. Kraut using six isomorphous crystallographic structures. Dihydrofolate reductase 3D structures. Categories : Dihydrofolate reductase Topic Page. Jump to: navigation , search. Show: Asymmetric Unit Biological Assembly. Export Animated Image. Views Article Discussion Edit this page History.
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Gene polymorphisms in the dihydrofolate reductase dhfr and dihydropteroate synthase dhps genes and structural modelling of the dhps gene in Colombian isolates of Toxoplasma gondii. ISSN Introduction: There are no reports describing polymorphisms in target genes of anti- Toxoplasma drugs in South American isolates. Objective: This study sought to perform cloning and sequencing of the dihydrofolate reductase dhfr and dihydropteroate-synthase dhps genes of the reference Rh strain and two Colombian isolates of Toxoplasma gondii.
Processing Please wait ES - Deficiencia de dihidrofolato reductasa-timidilato sintasa bifuncional en Tetrahymena y su uso. Publication Number Publication Date