Pyrimidine synthesis pathway

The **pyrimidine synthesis pathway** is a fundamental metabolic process responsible for generating pyrimidine nucleotides—essential building blocks for DNA and RNA. This process occurs via two main routes: 1. **De novo synthesis**, which constructs pyrimidines from simple precursors like glutamine, bicarbonate, aspartate, and ATP through a series of enzymatic steps. 2. **Salvage pathways**, which recycle preformed bases from degraded nucleic acids[1][3][5]. Key enzymes involved include carbamoyl phosphate synthetase II (CPS II), aspartate transcarbamoylase (ATCase), dihydroorotase (DHOase), dihydroorotate dehydrogenase (DHODH), orotate phosphoribosyltransferase (OPRT), and OMP decarboxylase[7]. The end products are uridine monophosphate (UMP) and cytidine triphosphate (CTP), vital for nucleic acid biosynthesis. This metabolic network is tightly regulated by feedback inhibition mechanisms; for example, UTP inhibits CPS II activity to prevent overproduction[5][7]. Dysregulation or genetic defects in this pathway can lead to diseases such as cancer or hereditary orotic aciduria. While individual enzymes within the pyrimidine synthesis pathway—such as DHODH—are considered therapeutic targets with drugs like leflunomide acting upon them[4], the entire "pyrimidine synthesis pathway" itself is not a single molecular target but rather a collection of enzymatic activities forming a biochemical route. **Note:** The entry "Pyrimidine synthesis pathway" refers to an entire metabolic process rather than an individual molecule/receptor/target. For structured drug discovery purposes, it is more appropriate to specify one of its constituent enzymes such as "Dihydroorotate dehydrogenase" when referring to actionable therapeutic targets[4].

Other names

De novo pyrimidine synthesis pathwayPyrimidine biosynthesisPyrimidine nucleotide metabolismPyrimidine salvage pathway

Inhibition of key enzymes in the pyrimidine synthesis pathway (e.g., DHODH inhibition blocks de novo pyrimidine production and impairs rapidly dividing cells)