# Threo-3-hydroxyaspartate ammonia-lyase

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threo-3-hydroxyaspartate ammonia-lyase
Identifiers
EC number 4.3.1.16
Databases
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MetaCyc metabolic pathway
PRIAM profile
PDB structures
Gene Ontology

In enzymology, a threo-3-hydroxyaspartate ammonia-lyase (EC 4.3.1.16) is an enzyme that catalyzes the chemical reaction

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.

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which is not consumed in the catalyzed reaction and can continue to act repeatedly. Because of this, only very small amounts of catalyst are required to alter the reaction rate in principle.

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei, and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

threo-3-hydroxy-L-aspartate ${\displaystyle \rightleftharpoons }$ oxaloacetate + NH3

Hence, this enzyme has one substrate, threo-3-hydroxy-L-aspartate, and two products, oxaloacetate and NH3.

Products are the species formed from chemical reactions. During a chemical reaction reactants are transformed into products after passing through a high energy transition state. This process results in the consumption of the reactants. It can be a spontaneous reaction or mediated by catalysts which lower the energy of the transition state, and by solvents which provide the chemical environment necessary for the reaction to take place. When represented in chemical equations products are by convention drawn on the right-hand side, even in the case of reversible reactions. The properties of products such as their energies help determine several characteristics of a chemical reaction such as whether the reaction is exergonic or endergonic. Additionally the properties of a product can make it easier to extract and purify following a chemical reaction, especially if the product has a different state of matter than the reactants. Reactants are molecular materials used to create chemical reactions. The atoms aren't created or destroyed. The materials are reactive and reactants are rearranging during a chemical reaction. Here is an example of reactants: CH4 + O2. A non-example is CO2 + H2O or "energy".

Ammonia is a compound of nitrogen and hydrogen with the formula NH3. A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a characteristic pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Ammonia is named for the Ammonians, worshipers of the Egyptian god Amun, who used ammonium chloride in their rituals.

## Nomenclature

This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is threo-3-hydroxy-L-aspartate ammonia-lyase (oxaloacetate-forming). Other names in common use include threo-3-hydroxyaspartate dehydratase, L-threo-3-hydroxyaspartate dehydratase, and threo-3-hydroxy-L-aspartate ammonia-lyase.

In biochemistry, a lyase is an enzyme that catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure. The reverse reaction is also possible. For example, an enzyme that catalyzed this reaction would be a lyase:

## Related Research Articles

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.This cycle was described in more detail later on by Ratner and Cohen. The urea cycle takes place primarily in the liver and, to a lesser extent, in the kidneys.

Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. Similar to all other amino acids it contains an amino group and a carboxylic acid. Its α-amino group is in the protonated –NH+
3
form under physiological conditions, while its α-carboxylic acid group is deprotonated −COO under physiological conditions. Aspartic acid has an acidic side chain (CH2COOH) which reacts with other amino acids, enzymes and proteins in the body. Under physiological conditions (pH 7.4) in proteins the side chain usually occurs as the negatively charged aspartate form, −COO. It is a non-essential amino acid in humans, meaning the body can synthesize it as needed. It is encoded by all the codons GAU and GAC.

Serine dehydratase or L-serine ammonia lyase (SDH) is in the β-family of pyridoxal phosphate-dependent (PLP) enzymes. SDH is found widely in nature, but its structural and chemical properties vary greatly among species. SDH is found in yeast, bacteria, and the cytoplasm of mammalian hepatocytes. The reaction it catalyzes is the deamination of L-serine to yield pyruvate, with the release of ammonia.

Aspartate dehydrogenase (EC 1.4.1.21) is an enzyme that catalyzes the chemical reaction

In enzymology, a L-aspartate oxidase (EC 1.4.3.16) is an enzyme that catalyzes the chemical reaction

In enzymology, an aspartate ammonia-lyase (EC 4.3.1.1) is an enzyme that catalyzes the chemical reaction

In enzymology, a D-serine ammonia-lyase (EC 4.3.1.18) is an enzyme that catalyzes the chemical reaction

In enzymology, an erythro-3-hydroxyaspartate ammonia-lyase (EC 4.3.1.20) is an enzyme that catalyzes the chemical reaction

In enzymology, a glucosaminate ammonia-lyase (EC 4.3.1.9) is an enzyme that catalyzes the chemical reaction

In enzymology, a L-serine ammonia-lyase (EC 4.3.1.17) is an enzyme that catalyzes the chemical reaction

In enzymology, a methylaspartate ammonia-lyase (EC 4.3.1.2) is an enzyme that catalyzes the chemical reaction

In enzymology, a 3-hydroxyaspartate aldolase is an enzyme that catalyzes the chemical reaction

In enzymology, a 4a-hydroxytetrahydrobiopterin dehydratase (EC 4.2.1.96) is an enzyme that catalyzes the chemical reaction

In enzymology, a D(−)-tartrate dehydratase (EC 4.2.1.81) is an enzyme that catalyzes the chemical reaction

In enzymology, a L(+)-tartrate dehydratase (EC 4.2.1.32) is an enzyme that catalyzes the chemical reaction

The purine nucleotide cycle is a metabolic pathway in which ammonia and fumarate are generated from aspartate and inosine monophosphate (IMP) in order to regulate the levels of adenine nucleotides, as well as to facilitate the liberation of ammonia from amino acids. This pathway was first described by John Lowenstein, who outlined its importance in processes including amino acid catabolism and regulation of flux through glycolysis and the Krebs cycle.

3-hydroxy-D-aspartate aldolase is an enzyme with systematic name 3-hydroxy-D-aspartate glyoxylate-lyase (glycine-forming). This enzyme catalyses the following chemical reaction

Threo-3-hydroxy-D-aspartate ammonia-lyase (EC 4.3.1.27, D-threo-3-hydroxyaspartate dehydratase) is an enzyme with systematic name threo-3-hydroxy-D-aspartate ammonia-lyase (oxaloacetate-forming). This enzyme catalyses the following chemical reaction

4-Hydroxy-tetrahydrodipicolinate synthase (EC 4.3.3.7, dihydrodipicolinate synthase, dihydropicolinate synthetase, dihydrodipicolinic acid synthase, L-aspartate-4-semialdehyde hydro-lyase (adding pyruvate and cyclizing), dapA (gene)) is an enzyme with the systematic name L-aspartate-4-semialdehyde hydro-lyase (adding pyruvate and cyclizing; (4S)-4-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinate-forming). This enzyme catalyses the following chemical reaction

## References

• Wada M, Matsumoto T, Nakamori S, Sakamoto M, Kataoka M, Liu JQ, Itoh N, Yamada H, Shimizu S (October 1999). "Purification and characterization of a novel enzyme, L-threo-3-hydroxyaspartate dehydratase, from Pseudomonas sp. T62". FEMS Microbiology Letters. 179 (1): 147–51. doi:10.1016/s0378-1097(99)00405-x. PMID   10481099.

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