The Importance of THF in DNA and RNA Synthesis

What is the function of dihydrofolate reductase in humans?

Dihydrofolate reductase (DHFR) is an enzyme that plays a crucial role in the synthesis of DNA, RNA, and proteins in humans. Its main function is to convert dihydrofolate (DHF) into tetrahydrofolate (THF), which is a key coenzyme involved in various biochemical reactions.

THF acts as a carrier of one-carbon units, which are vital for the synthesis of nucleotides, the building blocks of DNA and RNA. Specifically, THF provides the necessary carbon atoms in the forms of methyl, methylene, and formyl groups for the production of bases (adenine, guanine, cytosine, and thymine) and pyrimidines (uracil).

In the process of DNA synthesis, DHFR is responsible for regenerating THF from DHF, which is formed when THF donates its one-carbon unit during nucleotide synthesis. By converting DHF back to THF, DHFR ensures the continuous supply of THF for further DNA replication, repair, and cell division.

Moreover, THF is also required for the conversion of the amino acid serine to glycine, as well as for the production of certain amino acids such as methionine and histidine. THF also participates in the generation of the molecule S-adenosylmethionine (SAM), which is involved in various methylation reactions essential for gene expression regulation.

Overall, dihydrofolate reductase plays a critical role in maintaining the adequate supply of tetrahydrofolate, a coenzyme necessary for DNA, RNA, and protein synthesis, as well as for other important metabolic processes in human cells.

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