Table of Contents
What does Argininosuccinate synthetase do?
Argininosuccinate synthase or synthetase (ASS; EC 6.3. 4.5) is an enzyme that catalyzes the synthesis of argininosuccinate from citrulline and aspartate. In humans, argininosuccinate synthase is encoded by the ASS gene located on chromosome 9.
What is the function of argininosuccinate?
Argininosuccinate synthase plays an important role as the rate-limiting step in providing arginine for an assortment of metabolic processes, both catabolic and anabolic. Thus, the metabolic pathways in which argininosuccinate synthase participates are linked to the varied uses of the amino acid arginine.
What are the substrates used by Argininosuccinate synthetase?
The structures of the enzyme from Thermus thermophilus HB8 complexed with intact ATP and substrates (citrulline and aspartate) and with AMP and product (argininosuccinate) have been determined at 2.1- and 2.0-A resolution, respectively.
How is argininosuccinate formed?
Formation of Argininosuccinate The reaction is driven forward by hydrolysis of pyrophosphate to inorganic phosphate. Argininosuccinate formation is considered as the rate-limiting step for urea synthesis. This reaction incorporates the second nitrogen atom of the urea molecule donated by aspartate.
Can the Argininosuccinate synthetase deficiency be treated?
The main treatments for CTLN1 include a low-protein, high-calorie diet with amino acid supplements, particularly arginine. The Ucyclyd protocol, using buphenyl and ammonul, is used for treatment as well. Hyperammonemia is treated with hemodialysis; intravenous arginine, sodium benzoate, and sodium phenylacetate.
What are the stages of urea cycle?
A. Steps of Urea Cycle:
- Formation of Carbamoyl Phosphate:
- Synthesis of Citrulline:
- Synthesis of Argininosuccinate:
- Cleavage of Argininosuccinate:
- Glucogenic and Ketogenic Amino Acids:
- Oxidation of Carbon Skeleton of Amino Acids:
Where is argininosuccinate found?
chromosome 9
Argininosuccinate synthetase (ASS1) Located on the long arm of chromosome 9 (9q34. 11), ASS1 codes for argininosuccinate synthase, a homotetramer of 186 kDa involved in catalyzing the cytosolic condensation of citrulline and aspartate to argininosuccinic acid.
How is ammonia broken down?
When you eat proteins, the body breaks them down into amino acids. Ammonia is produced from leftover amino acids, and it must be removed from the body. The liver produces several chemicals (enzymes) that change ammonia into a form called urea, which the body can remove in the urine.
How do you prevent Citrullinemia?
For long-term treatment, people with citrullinemia type 1 are put on a special low- protein diet and are given medications and supplements that help keep their ammonia levels low. Infants are given a special low-protein formula instead of breast milk or regular formula.
How is Citrullinemia acquired?
SLC25A13: citrullinemia, type II Citrullinemia is an autosomal recessive disorder characterized by the accumulation of ammonia and other toxic substances in the blood due to malfunction of the urea cycle.
What are the 5 steps of urea cycle?