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The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). This cycle occurs in ureotelic organisms. The urea cycle converts highly toxic ammonia to urea for excretion. This cycle was the first metabolic cycle to be discovered (Hans Krebs and Kurt Henseleit, 1932), five years before the discovery of the TCA cycle. The urea cycle takes place primarily in the liver and, to a lesser extent, in the kidneys.
The Enzyme Commission number is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
Carbamoyl phosphate is an anion of biochemical significance. In land-dwelling animals, it is an intermediary metabolite in nitrogen disposal through the urea cycle and the synthesis of pyrimidines. Its enzymatic counterpart, carbamoyl phosphate synthetase I, interacts with a class of molecules called sirtuins, NAD dependent protein deacetylases, and ATP to form carbamoyl phosphate. CP then enters the urea cycle in which it reacts with ornithine to form citrulline. A defect in the CPS I enzyme, and a subsequent deficiency in the production of carbamoyl phosphate has been linked to hyper-ammonemia in humans.
Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
URB597 (KDS-4103) is a relatively selective inhibitor of the enzyme fatty acid amide hydrolase (FAAH). FAAH is the primary degradatory enzyme for the endocannabinoid anandamide and, as such, inhibition of FAAH leads to an accumulation of anandamide in the CNS and periphery where it activates cannabinoid receptors. URB597 has been found to elevate anandamide levels and have activity against neuropathic pain in a mouse model.
Carbamoyl phosphate synthetase I is a ligase enzyme located in the mitochondria involved in the production of urea. Carbamoyl phosphate synthetase I transfers an ammonia molecule from glutamine or glutamate to a molecule of bicarbonate that has been phosphorylated by a molecule of ATP. The resulting carbamate is then phosphorylated with another molecule of ATP. The resulting molecule of carbamoyl phosphate leaves the enzyme.
N-Acetylglutamate synthase deficiency is an autosomal recessive urea cycle disorder.
Dihydroorotase is an enzyme which converts carbamoyl aspartic acid into 4,5-dihydroorotic acid in the biosynthesis of pyrimidines. It forms a multifunctional enzyme with carbamoyl phosphate synthetase and aspartate transcarboymalase.
In enzymology, an alpha-amino-acid esterase (EC 3.1.1.43) is an enzyme that catalyzes the chemical reaction
In enzymology, an aminoacyl-tRNA hydrolase (EC 3.1.1.29) is an enzyme that catalyzes the chemical reaction
In enzymology, an aminoacylase (EC 3.5.1.14) is an enzyme that catalyzes the chemical reaction
In enzymology, a beta-ureidopropionase (EC 3.5.1.6) is an enzyme that catalyzes the chemical reaction
In enzymology, a carboxymethylhydantoinase (EC 3.5.2.4) is an enzyme that catalyzes the chemical reaction
In enzymology, Nα-benzyloxycarbonylleucine hydrolase (EC 3.5.1.64) is an enzyme that catalyzes the chemical reaction
In enzymology, a N-benzyloxycarbonylglycine hydrolase (EC 3.5.1.58) is an enzyme that catalyzes the chemical reaction
In enzymology, an ureidosuccinase (EC 3.5.1.7) is an enzyme that catalyzes the chemical reaction
Cytosol nonspecific dipeptidase is an enzyme. This enzyme catalyses the following chemical reaction
Acylaminoacyl-peptidase is an enzyme. This enzyme catalyses the following chemical reaction
