Sign Up for a Free Account

This is an image preview.
Start a Free Account
to view the full image.

Sign Up for a Free Account For information on discounts, see Plans & Pricing

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Ammonia detoxification through conversion to urea by enzymes

Ammonia is detoxified through its conversion to urea by the enzymes in the small boxes, whose abbreviations are spelled out below. CPS1 catalyzes the synthesis of carbamoyl phosphate from bicarbonate, ammonia, and ATP. Deficiency of CPS1 (highlighted in red) causes hyperammonemia along with accumulation of plasma glutamine and decreased plasma citrulline and arginine levels. Urinary orotic acid is decreased or normal. NAGS, N-acetylglutamate synthase; CPS1, carbamoyl phosphate synthetase 1; OTC, ornithine transcarbamylase; ASS, argininosuccinate synthetase; ASL, argininosuccinate lyase; ARG1, arginase 1. (Adapted from Zschocke and Hoffmann 2011.)

Related Article

Associated Disorders

  • Ataxia
  • Carbonic anhydrase VA deficiency
  • Cerebral palsy
  • Congenital hyperammonemia
  • Hyperinsulinism-hyperammonemia syndrome
  • Intellectual disability
  • Maple syrup urine disease
  • N-acetylglutamate synthase deficiency
  • Neuropsychiatric disease
  • Organic acidurias
  • Reye syndrome
  • Seizure disorder
  • Urea cycle disorders (others)
  • Valproate toxicity