key term - Carbamoyl phosphate

Definition

Carbamoyl phosphate is a crucial biochemical compound formed from the reaction of ammonia and bicarbonate, primarily in the mitochondria. It serves as an important substrate in the urea cycle and nucleotide synthesis, linking nitrogen metabolism with energy production and cellular building blocks.

5 Must Know Facts For Your Next Test

1. Carbamoyl phosphate is synthesized by the enzyme carbamoyl phosphate synthetase I (CPSI), which is activated by N-acetylglutamate.
2. In the urea cycle, carbamoyl phosphate reacts with ornithine to form citrulline, facilitating the detoxification of ammonia.
3. This compound is also involved in pyrimidine nucleotide synthesis, where it combines with aspartate to form dihydroorotate.
4. Carbamoyl phosphate plays a role in regulating the flow of nitrogen into amino acid and nucleotide biosynthesis pathways.
5. Dysregulation of carbamoyl phosphate metabolism can lead to disorders like hyperammonemia, affecting overall nitrogen balance in the body.

Review Questions

• How does carbamoyl phosphate function in the urea cycle and why is it important for detoxifying ammonia?
  • Carbamoyl phosphate functions as an essential substrate in the urea cycle by reacting with ornithine to form citrulline. This reaction helps convert toxic ammonia, generated from protein metabolism, into less harmful urea for excretion. The production of carbamoyl phosphate is vital for maintaining nitrogen balance and preventing ammonia toxicity in the body.
• Discuss the role of carbamoyl phosphate in nucleotide metabolism and how it relates to cellular functions.
  • In nucleotide metabolism, carbamoyl phosphate is a key precursor in the synthesis of pyrimidine nucleotides. It combines with aspartate to produce dihydroorotate, which is subsequently converted into uridine and cytidine nucleotides. These nucleotides are essential for DNA and RNA synthesis, highlighting the importance of carbamoyl phosphate in cellular functions related to genetic material and energy metabolism.
• Evaluate the consequences of impaired carbamoyl phosphate synthesis on human health and metabolic processes.
  • Impaired synthesis of carbamoyl phosphate can lead to severe metabolic disturbances, such as hyperammonemia, characterized by elevated levels of ammonia in the blood. This condition can result from deficiencies in the enzyme carbamoyl phosphate synthetase I or disruptions in its regulation. The resultant toxicity not only impacts neurological functions but also disrupts various metabolic processes dependent on nitrogen balance and nucleotide synthesis, illustrating the critical nature of this compound in overall health.

Related terms

Urea Cycle:

The metabolic pathway responsible for converting ammonia, a toxic byproduct of protein metabolism, into urea for excretion from the body.

Ornithine:

An amino acid that acts as a carrier in the urea cycle, combining with carbamoyl phosphate to form citrulline.

Nucleotide: The basic building blocks of nucleic acids (DNA and RNA), consisting of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups.