D-Aspartic Acid
D-Aspartic acid (CAS No.: 617-45-8), also known as (±)-Aspartic acid, D-Aminosuccinic acid, or 2-aminobutanedioic acid, is a racemic mixture consisting of equal amounts of the L-enantiomer (L-aspartic acid) and D-enantiomer (D-aspartic acid). It is an optically inactive alpha-amino acid with the molecular formula CHNO and a molecular weight of 133.10 g/mol.
Chemical & Physical Properties
- Appearance: White, odorless crystalline powder
- Melting Point: ~300 °C
- Solubility: Soluble in water and dilute hydrochloric acid; insoluble in ethanol and ether
- Optical Activity: Non-optically active ([α]D² = 0 ± 0.3° in dilute HCl)
- pKa Values: 2.28 (carboxyl), 9.36 (amino)
- Structure: Contains a central chiral carbon, an amino group (-NH), two carboxyl groups (-COOH), and a methylene side chain (-CH-)
Biological Significance
- L-Aspartic acid component: A proteinogenic amino acid (one of the 22 building blocks of proteins). It is non-essential in humans (synthesized endogenously) and plays critical roles in the urea cycle, citric acid cycle (Krebs cycle), and as a neurotransmitter.
- D-Aspartic acid component: Not incorporated into proteins but acts as a key regulator in neuroendocrine function, particularly in the hypothalamus, pituitary gland, and testes. It modulates the synthesis and release of hormones like , luteinizing hormone (LH), and gonadotropin-releasing hormone.
- DL-Aspartic acid: Lacks the specific biological activity of pure L- or D-isomers but serves as a cost-effective precursor and research tool.
Primary Applications
- Pharmaceutical & Biochemical Research
- Intermediate in peptide and drug synthesis.
- Standard reagent for chiral resolution studies and amino acid metabolism assays.
- Used in research investigating sperm quality, hormone regulation, and neurotransmission.
- Food & Feed Industry
- Precursor for flavor enhancers and acidulants in food seasonings.
- Component in racemic amino acid blends for nutritional supplements.
- Feed additive precursor (often enzymatically converted to L-aspartic acid).
- Industrial & Specialty Uses
- Raw material for biodegradable polymers.
- Chelating agent for metal ions in water treatment and analytical chemistry.
- Ingredient in cosmetics for skin/hair conditioning.
- Electrolyte additive in electrochemical applications.
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