Orotic acid

Overview

Chemical structure of orotic acid

Orotic acid is a heterocyclic compound and an acid that is a key intermediate in the biosynthesis of pyrimidines. It is also known as pyrimidinecarboxylic acid. Orotic acid is found in milk and is sometimes referred to as vitamin B13, although it is not a true vitamin.

Chemical Properties

Orotic acid has the chemical formula C_H_N_O_. It is a white, crystalline compound that is soluble in water. The structure of orotic acid consists of a pyrimidine ring with a carboxylic acid group attached.

Biological Role

Orotic acid plays a crucial role in the de novo synthesis of pyrimidine nucleotides. It is an intermediate in the pathway that leads to the formation of uridine monophosphate (UMP), which is a precursor to other pyrimidine nucleotides such as cytidine triphosphate (CTP) and thymidine triphosphate (TTP).

Metabolic Pathway

In the pyrimidine synthesis pathway, orotic acid is synthesized from dihydroorotate by the enzyme dihydroorotate dehydrogenase. Orotic acid is then converted to orotidine-5'-monophosphate (OMP) by the enzyme orotate phosphoribosyltransferase. OMP is subsequently decarboxylated to form UMP by the enzyme orotidine-5'-phosphate decarboxylase.

Clinical Significance

Elevated levels of orotic acid in the urine can be indicative of certain metabolic disorders, such as orotic aciduria and urea cycle disorders. Orotic aciduria is a rare genetic disorder caused by a deficiency in the enzymes involved in the conversion of orotic acid to UMP.

Dietary Sources

Orotic acid is naturally present in milk and dairy products. It is also found in small amounts in other foods such as root vegetables and beer.

Related Compounds

Orotic acid is related to other pyrimidine derivatives such as uracil, cytosine, and thymine. These compounds are essential components of nucleic acids and play a vital role in genetic information storage and transfer.

Related Pages

• Pyrimidine metabolism
• Nucleotide synthesis
• Metabolic disorders