dihydrofolaatreduktaas

Dihydrofolate reductase, often abbreviated as DHFR, is an essential enzyme found in nearly all organisms, from bacteria to humans. Its primary function is to catalyze the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF). This reduction is a critical step in the folate metabolic pathway, which is vital for the synthesis of purines, pyrimidines, and certain amino acids. These molecules are the building blocks of DNA, RNA, and proteins, making DHFR indispensable for cell growth and proliferation.

In humans, DHFR plays a crucial role in one-carbon metabolism. Tetrahydrofolate acts as a coenzyme, carrying one-carbon units that are transferred in various biochemical reactions. These reactions are necessary for DNA synthesis and repair, as well as for the metabolism of amino acids like methionine and serine. Without functional DHFR, cells cannot produce the necessary tetrahydrofolate to sustain these essential processes, leading to a disruption in nucleic acid synthesis and cell division.

The importance of DHFR in cellular processes has made it a significant target for various therapeutic agents. For example, methotrexate, a widely used chemotherapy drug, and trimethoprim, an antibiotic, are both DHFR inhibitors. By blocking the activity of DHFR, these drugs prevent the rapid proliferation of cancer cells or bacteria, respectively. The differential sensitivity of DHFR in various organisms and cell types allows for selective targeting.