De novo pyrimidine synthesis


Nucleotides are the building blocks of nucleic acids, such as DNA and RNA, which store and transmit genetic information in all living cells. Nucleotides consist of three components: a nitrogenous base, a pentose sugar, and one or more phosphate groups. The nitrogenous base can be either a purine (adenine or guanine) or a pyrimidine (cytosine, thymine, or uracil).

Nucleotides have many important functions in the cell, besides being the monomers of nucleic acids. They serve as energy carriers (e.g., ATP and GTP), coenzymes (e.g., NAD and FAD), signaling molecules (e.g., cAMP and cGMP), and precursors of other biomolecules (e.g., amino acids and lipids). Nucleotides also regulate many cellular processes, such as metabolism, transcription, translation, replication, and repair.

Because of their essential roles in the cell, nucleotides must be synthesized and maintained at adequate levels. There are two major pathways for nucleotide synthesis: de novo and salvage. De novo synthesis refers to the formation of nucleotides from simple precursors, such as amino acids, carbon dioxide, and ribose-5-phosphate. Salvage synthesis refers to the recycling of nucleotides from degraded nucleic acids or other sources.

In this article, we will focus on the de novo synthesis of pyrimidine nucleotides, which are essential for DNA and RNA synthesis, as well as for other cellular functions. We will discuss the location, substrates, products, reactions, enzymes, regulation, alternative pathways, diseases, and significance of this pathway in biology and medicine.