Ornithine transcarbamylase

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Ornithine transcarbamylase
Ornithine transcarbamylase
Ribbon model of the trimer according to PDB  1OTH

Existing structural data : 1c9y , 1ep9 , 1fvo , 1oth

Properties of human protein
Mass / length primary structure 322 amino acids
Secondary to quaternary structure Homotrimer
Identifier
Gene name OTC
External IDs
Enzyme classification
EC, category 2.1.3.3 ,  transferase
Response type Transfer of an aminocarbonyl residue
Substrate Carbamoyl phosphate + ornithine
Products Phosphate + citrulline
Occurrence
Parent taxon Creature

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 broken down in the reverse reaction . In humans, OTC is found primarily in the liver and small intestine . Mutations in the OTC - gene can and familial OTC deficiency, this to hyperammonemia lead.

At 1: 14,000, OTC deficiency is the most common urea cycle defect . Two OTC variants were associated with an increased risk of Alzheimer's disease in a French study . Furthermore, in the case of a congenital deficiency during therapy with valproic acid due to hyperammonaemia, valproic acid-associated encephalopathy can occur.

Catalyzed equilibrium

Ornithine+ Carbamoyl phosphate⇔ Citrulline+ P i

An aminocarbonyl residue is transferred from carbamoyl phosphate to L-ornithine and L-citrulline is formed.

Individual evidence

  1. ↑ Homologues at OMA
  2. ↑ InterPro entry
  3. ↑ UniProt P00480
  4. ↑ Hansmannel F, Lendon C, Pasquier F, et al. : Is the ornithine transcarbamylase gene a genetic determinant of Alzheimer's disease? . In: Neurosci. Lett. . 449, No. 1, January 2009, pp. 76-80. doi : 10.1016 / j.neulet.2008.10.081 . PMID 18983895 .
  5. ↑ Bensemain F, Hot D, Ferreira S, et al. : Evidence for induction of the ornithine transcarbamylase expression in Alzheimer's disease . In: Mol. Psychiatry . 14, No. 1, January 2009, pp. 106-16. doi : 10.1038 / sj.mp.4002089 . PMID 17893704 .

Web links

Wikibooks: Urea Cycle  - Learning and Teaching Materials