D-Aspartic Acid

D-Aspartic acid is the R-enantiomer of aspartic acid: (2R)-2-aminobutanedioic acid, CAS 1783-96-6, EC 217-234-6, C4H7NO4, molecular weight 133.10. It is a different article from the ordinary protein amino acid L-aspartic acid (CAS 56-84-8) and from the racemate, and ordering the wrong isomer is the commonest costly error on this line, so every Thovek offer, COA and packing mark states the D-form explicitly. Unlike the L-form it is not used in ribosomal protein synthesis; it is one of only two D-amino acids that occur commonly in mammalian tissue, present in free form in neuroendocrine tissue and built into a small number of peptides. The distinguishing analytical handle is optical: the D-form is levorotatory, reported at about -24 degrees at c = 2.3 in 6 M hydrochloric acid and -25.8 degrees at c = 5 in 5 N hydrochloric acid, where the L-form under comparable conditions is dextrorotatory. The material is a white to off-white crystalline powder, produced by chiral resolution of racemic aspartic acid or by enzymatic routes, both of which start from petrochemical or fermentation intermediates rather than from any animal or dairy raw material. It is sparingly soluble in water at roughly 4.5 g/L, dissolves readily in dilute hydrochloric acid and in 1 N ammonium hydroxide, and decomposes above 300 C instead of melting sharply. Its three ionisable groups have pKa values near 1.99, 3.90 and 9.90, so in a neutral drink powder it behaves as an acidic, negatively charged solid. Because enantiomeric purity is the whole point of the product, Thovek releases each lot on chiral HPLC or specific rotation against the L-isomer limit the buyer nominates, alongside assay, moisture, residue on ignition, chloride, sulphate, ammonium, ICP-MS heavy metals and full microbiology. Buyers are principally sports nutrition and men's category brands and their contract manufacturers, who formulate it as a single-ingredient powder, in capsules and tablets, in effervescent and flavoured drink sticks and in stacked amino acid products; peptide chemistry and research laboratories take smaller high-purity quantities. Thovek supplies the ingredient on its own chemistry and specification only. We describe what the molecule is and how it is controlled, and make no therapeutic, hormonal or disease claim of any kind; the brand owner is responsible for the claims made on the finished label and for confirming that a D-amino acid is permitted in supplements in the destination market, since national positive lists differ.