Nucleotide synthesis pathways

Nucleotide synthesis pathways encompass the complex biochemical processes responsible for the production of purine and pyrimidine nucleotides, which serve as the essential building blocks for DNA and RNA (StatPearls, 2023). These pathways are divided into de novo synthesis, which constructs nucleotides from basic precursors like amino acids and ribose-5-phosphate, and salvage pathways, which recycle free bases and nucleosides from degraded nucleic acids (NCBI, 2022). Because rapidly proliferating cells, such as malignant cancer cells and activated lymphocytes, have an outsized requirement for nucleotides to support genome replication, these pathways are critical therapeutic targets in oncology and immunology (Nature Reviews Cancer, 2021). Antimetabolite drugs like Methotrexate and 5-Fluorouracil exploit this dependency by inhibiting key enzymes, thereby starving the cell of the components necessary for survival and division (PubChem, 2024). Beyond cancer, the modulation of these pathways is vital for treating autoimmune conditions and viral infections, where limiting nucleotide availability can suppress pathological immune responses or viral replication (Journal of Biological Chemistry, 2020). However, because these pathways are also active in healthy, rapidly dividing tissues like the bone marrow and intestinal epithelium, therapeutic intervention often results in significant side effects such as myelosuppression and mucositis (NIH, 2023).

Other names

Purine and pyrimidine metabolismDe novo nucleotide synthesisNucleotide salvage pathwaysNucleotide biosynthesisNucleic acid synthesis

Drugs targeting these pathways, primarily antimetabolites, act as structural analogs of natural nucleotides or their precursors. They competitively or irreversibly inhibit rate-limiting enzymes such as Dihydrofolate reductase (DHFR), Thymidylate synthase (TS), Inosine monophosphate dehydrogenase (IMPDH), and Ribonucleotide reductase (RNR), leading to the depletion of intracellular dNTP pools and the subsequent inhibition of DNA and RNA synthesis (StatPearls, 2023; PubChem, 2024).