|Systematic (IUPAC) name|
|Mol. mass||156.10 g/mol|
| (what is this?)
Orotic acid is a heterocyclic compound and an acid; it is also known as pyrimidinecarboxylic acid. Historically it was believed to be part of the Vitamin B complex and was called vitamin B13, but it is now known that it is not a vitamin.
The compound is manufactured in the body by intestinal flora. It is sometimes used as a mineral carrier in some dietary supplements (to increase their bioavailability), most commonly for lithium orotate.
Synthesis of orotate 
Dihydroorotate is synthesized to orotic acid by the enzyme dihydroorate dehydrogenase, where it later combines with phosphoribosyl pyrophosphate (PRPP) to form orotidine-5'-monophosphate (OMP). A distinguishing characteristic of pyrimidine synthesis is that the pyrimidine ring is fully synthesized before being attached to the ribose sugar, whereas purine synthesis happens by building the base directly on the sugar.
Orotic acid diseases 
In ornithine transcarbamoylase deficiency, an X-linked inherited and the most common urea cycle disorder, excess carbamoyl phosphate is converted into orotic acid. This leads to an increased serum ammonia level, increased serum and urinary orotic acid levels and a decreased serum BUN level. This also leads to an increased urinary orotic acid excretion, because the orotic acid is not being properly utilized and must be eliminated. The hyperammonemia depletes alpha-ketoglutarate leading to the inhibition of the tricarboxylic acid cycle (TCA) decreasing ATP production.
Orotic acid can be mutagenic (causes mutations) in mammalian somatic cells. It is also mutagenic for bacteria and or yeast.
See also 
- Lippincott. Biochemistry 4th Edition. 2008
- Orotic Acid at the US National Library of Medicine Medical Subject Headings (MeSH)
- Overview at ggc.org
- Overview at greatvistachemicals.com
- Overview of Potential Metabolic Antagonists