L-α-Aminoadipic Acid: Properties, Biochemistry & Research Uses

L-α-Aminoadipic acid is a naturally occurring, non-proteinogenic amino acid that serves as a key intermediate in the lysine biosynthesis and degradation pathways and has important applications in neuroscience, metabolic research, and fungal biochemistry.

CAS Number

1118-90-7

Molecular Formula

C₆H₁₁NO₄

Molecular Weight

161.16 g/mol

Appearance

White to off-white crystalline powder

Solubility

Soluble in water; sparingly soluble in ethanol

Optical Activity

L-configuration (S); optically active

Metabolic Role

Intermediate in lysine catabolism and fungal lysine biosynthesis (α-aminoadipate pathway)

Chemical Identity and Physical Properties

L-α-Aminoadipic acid (L-2-aminohexanedioic acid; CAS 1118-90-7) is the L-enantiomer of α-aminoadipic acid, a six-carbon dicarboxylic amino acid structurally analogous to glutamic acid but with one additional methylene group. Its molecular formula is C₆H₁₁NO₄ and molecular weight is 161.16 g/mol. The compound exists as a zwitterion at physiological pH and carries both an α-amino group and two carboxylate moieties, giving it amphoteric character.

The pure compound is a white to off-white crystalline powder with good water solubility, which facilitates its preparation as aqueous stock solutions for cell culture and biochemical assays. It is sparingly soluble in ethanol and practically insoluble in nonpolar organic solvents. The L-configuration (S) is the biologically relevant stereoisomer found in living organisms.

Biochemical Roles and Metabolic Pathways

L-α-Aminoadipic acid occupies a central position in amino acid metabolism in two distinct contexts. First, in mammals, it is a key intermediate in the catabolism of L-lysine and L-hydroxylysine via the saccharopine pathway, connecting lysine degradation to the tricarboxylic acid (TCA) cycle through eventual conversion to acetyl-CoA. Second, in fungi and certain bacteria, L-α-aminoadipic acid is an essential intermediate and a metabolic precursor in the α-aminoadipate (AAA) pathway for de novo lysine biosynthesis—a pathway entirely absent in animals and plants, which use the diaminopimelate (DAP) route instead.

In the fungal AAA pathway, L-α-aminoadipic acid is also a direct precursor to the tripeptide δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine (ACV), the committed intermediate in the biosynthesis of β-lactam antibiotics such as penicillin and cephalosporin. This makes L-α-aminoadipic acid critically important in industrial microbiology and antibiotic research.

Additionally, L-α-aminoadipic acid is produced endogenously in humans as a metabolite of tryptophan catabolism through the kynurenine pathway, where it appears as a minor downstream product, reflecting the metabolic intersection of several amino acid degradation routes.

Research Applications

Neuroscience and Astrocyte Biology: L-α-Aminoadipic acid has been extensively studied as a selective astrocyte toxin in the central nervous system. When administered locally in vivo or applied to primary cultures, it selectively damages astrocytes while largely sparing neurons and oligodendrocytes. This selectivity makes it a valuable experimental tool for dissecting the roles of astroglia in neural circuit function, neuroprotection, and neurological disease models. Researchers use it to create astrocyte-depleted preparations to study glial–neuronal interactions.

Metabolic and Enzymological Studies: As an authentic biosynthetic intermediate, L-α-aminoadipic acid is used as a substrate or reference compound in enzyme kinetics assays involving aminoadipate aminotransferase, homoisocitrate dehydrogenase, and related enzymes of the lysine pathway. It is also applied as an analytical standard in metabolomics and amino acid profiling by HPLC or LC-MS/MS.

Antibiotic Biosynthesis Research: Studies of β-lactam antibiotic production in Penicillium and Acremonium species utilize L-α-aminoadipic acid as a substrate for ACV synthetase activity assays, supporting strain improvement and biosynthetic pathway elucidation.

Biomarker Research: Elevated plasma levels of α-aminoadipic acid have been associated with diabetes risk and metabolic syndrome in epidemiological studies, positioning it as a potential biomarker in clinical metabolomics workflows.

Handling, Storage, and Solution Preparation

Storage: Store L-α-aminoadipic acid as a dry solid at room temperature (15–25 °C) in a tightly sealed container, protected from moisture and prolonged exposure to light. Under these conditions the compound is stable for an extended period. Refer to the product-specific Certificate of Analysis (CoA) for confirmed shelf life.

Solution Preparation: The compound dissolves readily in water. For aqueous stock solutions, dissolve in deionized or ultrapure water to the desired concentration (typical working concentrations in cell-based assays range from 1–10 mM, though optimal concentrations should be determined empirically for each application). If needed, gentle warming and stirring may assist dissolution. Adjust pH with dilute NaOH or HCl as appropriate for the experimental system. Filter-sterilize (0.22 µm) solutions intended for cell culture.

Safety: Handle with standard laboratory precautions—wear appropriate personal protective equipment (gloves, lab coat, eye protection). Consult the Safety Data Sheet (SDS) prior to use for complete hazard information. Avoid inhalation of dust.

Why Choose Aladdin Scientific

Aladdin Scientific's L-α-Aminoadipic acid (SKU: A100535) is manufactured and quality-controlled to meet the demanding purity requirements of biochemical and cell-biology research. Each lot is accompanied by a Certificate of Analysis documenting purity, identity (including NMR and/or HPLC verification), and physicochemical data, enabling researchers and lab managers to validate reagent quality before use. Our competitive pricing, reliable inventory, and responsive technical support make Aladdin Scientific a trusted partner for procurement of specialty amino acids and biochemical building blocks.

Frequently asked questions

What is L-α-aminoadipic acid used for in neuroscience research?

L-α-Aminoadipic acid is used as a selective astrocyte toxin. When applied in vivo or in vitro, it preferentially damages astrocytes while largely sparing neurons, making it a valuable tool for studying astrocyte function and glial–neuronal interactions in the central nervous system.

How should I prepare a stock solution of L-α-aminoadipic acid?

L-α-Aminoadipic acid dissolves readily in water. Prepare stock solutions by dissolving the powder in deionized or ultrapure water at your desired concentration, adjusting pH as needed with dilute NaOH or HCl. For cell culture applications, filter-sterilize using a 0.22 µm membrane filter before use.

What is the role of L-α-aminoadipic acid in lysine biosynthesis?

In fungi and certain bacteria, L-α-aminoadipic acid is a central intermediate in the α-aminoadipate (AAA) pathway for de novo lysine biosynthesis. This pathway is unique to these organisms and is absent in mammals and plants, making it an attractive target for antifungal drug development. The compound also serves as a precursor for β-lactam antibiotic biosynthesis in penicillin- and cephalosporin-producing fungi.

Is L-α-aminoadipic acid related to diabetes risk?

Epidemiological metabolomics studies have reported associations between elevated plasma levels of α-aminoadipic acid and increased risk of type 2 diabetes and metabolic syndrome. However, the mechanistic basis of this association is still under investigation, and it is currently used primarily as a research biomarker rather than a clinical diagnostic tool.

How should L-α-aminoadipic acid be stored to maintain stability?

Store the dry solid at room temperature (15–25 °C) in a tightly sealed container, protected from moisture and light. Always consult the Certificate of Analysis provided with your lot for specific storage recommendations and confirmed expiration date.

References

1. Broquist HP. Lysine biosynthesis (yeast and bacteria) via the α-aminoadipate pathway. Methods Enzymol. 1971.
2. Bhattacharya SK, Bhattacharya D. Selective astrocytic toxicity of alpha-aminoadipic acid in vivo. Neuroscience. (Year not confirmed in source material.)
3. Wang TJ, et al. Metabolite profiles and the risk of developing diabetes. Nat Med. 2011.
4. Bhattacharya SK. α-Aminoadipic acid as a selective gliotoxin. Methods Enzymol. (Year not confirmed in source material.)

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