Ketoglutaric acid

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Ketoglutaric acid

a-Ketoglutaric acid is one of two ketone

Ketone

In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
derivatives of glutaric acid

Glutaric acid

Glutaric acid is the organic compound with the chemical formula HO2C3CO2H. Although the related "linear" dicarboxylic acids adipic acid and succinic acids are water-soluble only to a few percent at room temperature, the water-solubility of glutaric acid is over 50%....
. (The term "ketoglutaric acid," when not further qualified, almost always refers to the alpha variant. ß-Ketoglutaric acid

Acetonedicarboxylic acid

Acetonedicarboxylic acid or 3-oxoglutaric acid is a simple carboxylic acid, which may be used as a building block in organic chemistry.It is commercially available....
varies only by the position of the ketone functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
, and is much less common.)

Its anion, a-ketoglutarate (also called oxo-glutarate) is an important biological compound. It is the keto acid

Keto acid

Keto acids are organic compound acids containing a ketone functional group and a carboxylic acid group.Common types of keto acids include:...
produced by de-amination of glutamate, and is an intermediate in the Krebs cycle.

toglutaric acid is a key intermediate in the Krebs cycle, coming after isocitrate and before succinyl CoA.

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Encyclopedia

a-Ketoglutaric acid is one of two ketone

Ketone

Glutaric acid

Acetonedicarboxylic acid

Functional group

Keto acid

Functions

Krebs cycle

a-Ketoglutaric acid is a key intermediate in the Krebs cycle, coming after isocitrate and before succinyl CoA. Anaplerotic reactions

Anaplerotic reactions

Anaplerotic:Ana-up,Plerotikos-to fillAnaplerotic reactions are those that form intermediates of the TCA or citric acid cycle. The malate is created by PEP carboxylase and malate dehydrogenase in the cytosol....
can replenish the cycle at this juncture by synthesizing a-ketoglutarate from transamination of glutamate, or through action of glutamate dehydrogenase

Glutamate dehydrogenase

Glutamate dehydrogenase is an enzyme, present in mitochondria of eukaryotes, as are some of the other enzymes required for urea synthesis, that converts glutamate to a-Ketoglutaric acid, and vice versa....
on glutamate.

Formation of amino acids

Glutamine

Glutamine is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide formed by replacing the side-chain hydroxyl of glutamic acid with an amine functional group....
is synthesized from glutamate by glutamine synthase, which utilizes an ATP to form glutamyl phosphate; this intermediate is attacked by ammonia as a nucleophile giving glutamine and inorganic phosphate.

Nitrogen transporter

Another function is to combine with nitrogen released in the cell, therefore preventing nitrogen overload.

a-Ketoglutarate is one of the most important nitrogen transporter in metabolic pathways. The amino groups of amino acids are attached to it by transamination

Transamination

There are two chemical reactions known as transamination . The first is the reaction between an amino acid and an alpha-keto acid. The amino group is transferred from the former to the latter; this results in the amino acid being converted to the corresponding a-keto acid, while the reactant a-keto acid is converted to the corresponding amin...
and carried to the liver where the urea cycle

Urea cycle

The urea cycle is a cycle of biochemistry reactions occurring in many animals that produces urea 2carbonoxygen from ammonia . This cycle was the first metabolic cycle discovered ....
takes place.

a-Ketoglutarate is transaminated, along with glutamine, to form the excitatory neurotransmitter

Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
glutamate. Glutamate can then be decarboxylated (requiring vitamin B₆

Vitamin B6

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation....
) into the inhibitory neurotransmitter GABA

Gabâ

Gab? or gabaa, for the Cebuano people , is the concept of a non-human and non-divine, imminent Retributive justice. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions....
.

It is reported that high ammonia and/or high nitrogen levels may occur with high protein

Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
intake, excessive aluminum exposure, Reye's syndrome

Reye's syndrome

Reye's syndrome is a potentially fatal disease that causes numerous detrimental effects to many organs, especially the brain and liver. It is associated with aspirin consumption by children with viral diseases such as chickenpox....
, cirrhosis

Cirrhosis

Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver Tissue by fibrous scar tissue as well as regenerative Nodule , leading to progressive loss of liver function....
, and urea cycle disorder

Urea cycle disorder

An urea cycle disorder or urea cycle defect is a genetic disorder caused by a deficiency of one of the enzymes in the urea cycle which is responsible for removing ammonia from the blood stream....
.

Relationship to molecular oxygen

Acting as a co-substrate, it also plays important function in oxidation reactions involving molecular oxygen.

Molecular oxygen (O₂) directly oxidizes many compounds to produce useful products in an organism, such as antibiotic

Antibiotic

In common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria. Antibiotics belong to the group of antimicrobial compounds used to treat infections caused by microorganisms, including fungus and protozoa....
s, etc., in reactions catalyzed by oxygenase

Oxygenase

An oxygenase is any enzyme that redox a Substrate by transferring the oxygen from molecular oxygen O2 to it. The oxygenases form a class of oxidoreductases; their EC number is EC 1.13 or EC 1.14....
s. In many oxygenases, a-ketoglutarate helps the reaction by being oxidized together with the main substrate. In fact, one of the a-ketoglutarate-dependent oxygenases is an O₂ sensor, informing the organism the oxygen level in its environment.

Dietary supplement

a-Ketoglutaric acid is sold as a dietary supplement

Dietary supplement

A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to provide nutrients, such as vitamins, Dietary minerals, fatty acids or amino acids, that are missing or are not consumed in sufficient quantity in a person's diet ....
and to body builders as AKG or a-KG. Some believe it increases stamina.

Production

a-Ketoglutarate can be produced by:

Oxidative decarboxylation
Oxidative decarboxylation

Pyruvate decarboxylation is the biochemical reaction that uses pyruvate to form acetyl-CoA, releasing NADH, a reducing equivalent, and carbon dioxide....
of isocitrate by isocitrate dehydrogenase
Isocitrate dehydrogenase

Isocitrate dehydrogenase and , also known as IDH, is an enzyme which participates in the citric acid cycle. It catalyzes the third step of the cycle: the oxidative decarboxylation of isocitrate, producing Ketoglutaric acid and carbon dioxide while converting Nicotinamide adenine dinucleotide to Nicotinamide adenine dinucleotide....
;
Oxidative deamination
Oxidative deamination

Oxidative deamination is a form of deamination that generates oxoacids in the liver.The presence of nitrous acid can cause Transition mutations, by converting cytosine to uracil....
of glutamate by glutamate dehydrogenase
Glutamate dehydrogenase

Glutamate dehydrogenase is an enzyme, present in mitochondria of eukaryotes, as are some of the other enzymes required for urea synthesis, that converts glutamate to a-Ketoglutaric acid, and vice versa....
.

Alpha-ketoglutarate can be used to produce:

Creatine-alpha ketoglutarate
Creatine-alpha ketoglutarate

Creatine-alpha-ketoglutarate is a salt formed from alpha-Ketoglutaric acid and creatine. It is sold as a fitness supplement; however, its effects are experimentally unproven....