DNA and nucleotide-synthesis enzyme

DNA and nucleotide-synthesis enzymes represent a broad class of catalytic proteins responsible for the production of nucleotide precursors and the assembly of DNA polymers. This group includes critical enzymes such as dihydrofolate reductase (DHFR), thymidylate synthase (TS), ribonucleotide reductase (RNR), and various DNA polymerases, which together ensure a sufficient supply of deoxyribonucleotides for genome replication and repair (StatPearls, 2023; NIH, 2024). Because high rates of DNA synthesis are a hallmark of rapidly proliferating cells, these enzymes are primary therapeutic targets in oncology, immunology, and infectious disease (PubMed, 2022). Antimetabolite drugs, such as methotrexate and 5-fluorouracil, mimic natural substrates to inhibit these enzymes, thereby depleting intracellular nucleotide pools or causing direct DNA damage. This interference typically leads to cell cycle arrest in the S-phase and subsequent apoptosis, making these enzymes pivotal in controlling tumor growth and pathogen replication. However, because these enzymes are also active in healthy dividing tissues like bone marrow and the gastrointestinal lining, drugs targeting them often exhibit significant systemic toxicities. Understanding the specific expression and activity of these enzymes is vital for optimizing therapeutic efficacy and minimizing toxicity in clinical practice.

Other names

Nucleotide biosynthetic enzymesDNA synthesis machineryAntimetabolite targetsDNA replication enzymes

Inhibition of nucleotide precursor synthesis or DNA polymerization, leading to depletion of dNTP pools, DNA chain termination, and S-phase cell cycle arrest.