''N''-Acetylaspartic acid, or ''N''-acetylaspartate (NAA), is a derivative of aspartic acid with a formula of C₆H₉NO₅ and a molecular weight of 175.139. NAA is the second-most-concentrated

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

in the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

after the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

glutamate. It is detected in the adult brain in

neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. ...

oligodendrocyte Oligodendrocytes (), or oligodendroglia, are a type of neuroglia whose main functions are to provide support and insulation to axons in the central nervous system of jawed vertebrates, equivalent to the function performed by Schwann cells in the ...

s and

myelin Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be ...

and is synthesized in the mitochondria from the amino acid aspartic acid and

acetyl-coenzyme A Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for ...

Function

The various functions served by NAA are under investigation, but the primary proposed functions include: * Neuronal

osmolyte Osmolytes are low-molecular weight organic compounds that influence the properties of biological fluids. Their primary role is to maintain the integrity of cells by affecting the viscosity, melting point, and ionic strength of the aqueous solution. ...

that is involved in fluid balance in the brain * Source of acetate for

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids includ ...

and myelin synthesis in oligodendrocytes, the glial cells that myelinate neuronal axons * Precursor for the synthesis of the neuronal dipeptide N-Acetylaspartylglutamate * Contributor to energy production from the amino acid glutamate in neuronal mitochondria In the brain, NAA was thought to be present predominantly in neuronal cell bodies, where it acts as a neuronal marker, but it is also free to diffuse throughout neuronal fibers.

Applications

However, the recent discovery of a higher concentration of NAA in myelin and oligodendrocytes than in neurons raises questions about the validity of the use of NAA as a neuronal marker. NAA gives off the largest signal in

magnetic resonance spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique to observe local magnetic fields around atomic nuclei. The sample is placed in a magnetic fie ...

of the human brain. The levels measured there are decreased in numerous neuropathological conditions ranging from brain injury to stroke to Alzheimer's disease. This fact makes NAA a potential diagnostic molecule for doctors treating patients with brain damage or disease. NAA may be a marker of creativity. High NAA levels in the

hippocampus The hippocampus (via Latin from Greek , ' seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, ...

are related to better

working memory Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...

performance in humans. NAA may function as a neurotransmitter in the brain by acting on

metabotropic glutamate receptor The metabotropic glutamate receptors, or mGluRs, are a type of glutamate receptor that are active through an indirect metabotropic process. They are members of the group C family of G-protein-coupled receptors, or GPCRs. Like all glutamate re ...

References

External links

GeneReviews/NCBI/UW/NIH entry on Canavan disease
{{DEFAULTSORT:Acetylaspartic acid, N- Amino acid derivatives

Function

Applications

See also

References

Further reading

External links