Ornithine transcarbamylase

• OMIM: 300461
• UniProt: P00480

Ornithine transcarbamylase (OTC) is the enzyme that catalyzes the conversion of ornithine to citrulline. This is a partial step in the urea cycle of vertebrates, but also in the biosynthesis of the amino acid arginine in all living things. In some bacteria arginine is degraded to the reverse reaction. In humans, OTC is found mainly in the liver and small intestine. Mutations in the OTC gene can be familial OTC deficiency, and this lead to hyperammonemia.

OTC deficiency is the most common urea cycle defect with 1:14.000. Two OTC variants were in a French study associated with increased risk for Alzheimer 's disease.

Catalysed equilibrium

⇔ Pi

A aminocarbonyl is transferred from carbamoyl phosphate to L -ornithine and L-citrulline produced.