L-ASPARTIC ACID

L-Aspartic Acid is the L-form of the aspartic acid. 
L-Aspartic Acid is one of the 20 amino acids that used in the protein synthesis. 
L-Aspartic Acid is the non-essential amino acids for humans as it can be synthesized in vivo. 

CAS:    56-84-8
MF:    C4H7NO4
MW:    133.1
EINECS:    200-291-6

Synonyms
L-Aspartic acidUSP, 98.5-101.5% (Titration: anhydrous basis);(s)-butanedioicaci;alpha-Aminosuccinic acid;Asparagic acid;asparagicacid;Asparaginic acid;asparaginicacid;asparaginsaeure

L-Aspartic Acid is important in the synthesis of other amino acids and some nucleotides, and is a metabolite in the citric acid and urea cycles. 
In animals, L-Aspartic Acid may be used as a neurotransmitter. 
L-Aspartic Acid can be chemically synthesize from the diethyl sodium phthalimidomalonate. 
Currently, almost all the aspartic acids are manufactured in China. 
L-Aspartic Acid2s application include being used as low calorie sweetener (as the part of the aspartame), scale and corrosion inhibitor, and in resins. 
One of its growing applications is for the manufacturing of biodegradable superabsorbent polymer, polyaspartic acid. 
L-Aspartic Acid can also be used in fertilizer industry to improve water retention and nitrogen uptake.
Aspartic acid was first discovered in 1827 by Plisson, derived from asparagine, which had been isolated from asparagus juice in 1806, by boiling with a base.
The L-enantiomer of aspartic acid.

L-Aspartic Acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins.
The L-isomer of aspartic acid is one of the 22 proteinogenic amino acids, i.e., the building blocks of proteins. 
L-Aspartic Acid is one of two D-amino acids commonly found in mammals.
Apart from a few rare exceptions, L-Aspartic Acid is not used for protein synthesis but is incorporated into some peptides and plays a role as a neurotransmitter/neuromodulator.

Like all other amino acids, L-Aspartic Acid contains an amino group and a carboxylic acid. 
L-Aspartic Acid's α-amino group is in the protonated –NH+
3 form under physiological conditions, while its α-carboxylic acid group is deprotonated −COO− under physiological conditions. 
L-Aspartic Acid has an acidic side chain (CH2COOH) which reacts with other amino acids, enzymes and proteins in the body.
Under physiological conditions (pH 7.4) in proteins the side chain usually occurs as the negatively charged aspartate form, −COO−.
L-Aspartic Acid is a non-essential amino acid in humans, meaning the body can synthesize it as needed. 
L-Aspartic Acid is encoded by the codons GAU and GAC.

In proteins aspartate sidechains are often hydrogen bonded to form asx turns or asx motifs, which frequently occur at the N-termini of alpha helices.
Aspartic acid, like glutamic acid, is classified as an acidic amino acid, with a pKa of 3.9; however, in a peptide this is highly dependent on the local environment, and could be as high as 14.
The one-letter code D for aspartate was assigned arbitrarily, with the proposed mnemonic asparDic acid.

L-Aspartic Acid Chemical Properties
Melting point: >300 °C (dec.)(lit.)
Alpha: 25 º (c=8, 6N HCl)
Boiling point: 245.59°C (rough estimate)
Density: 1.66
Bulk density: 430kg/m3
FEMA: 3656 | L-ASPARTIC ACID
Refractive index: 1.4540 (estimate)
Storage temp.: Store below +30°C.
Solubility H2O: 5 mg/mL
Form: powder
pka: 1.99(at 25℃)
Color: White
PH: 2.5-3.5 (4g/l, H2O, 20℃)
Odor: acid taste
Biological source: synthetic
Optical Rotation: [α]20/D +24.7±1°, c = 5% in 5 M HCl
Odor Type: odorless
Water Solubility: 5 g/L (25 ºC)
λmax λ: 260 nm Amax: 0.20
λ: 280 nm Amax: 0.10
Merck: 14,840
JECFA Number: 1429
BRN: 1723530
Stability: Stable. Combustible. Incompatible with strong oxidising agents.
InChIKey: CKLJMWTZIZZHCS-REOHCLBHSA-N
LogP: -0.67
CAS DataBase Reference: 56-84-8(CAS DataBase Reference)
NIST Chemistry Reference: L-Aspartic Acid(56-84-8)
EPA Substance Registry System: L-Aspartic Acid (56-84-8)

L-Aspartic Acid is white crystal or crystalline powder, slightly sour in taste. 
Soluble in boiling water, slightly soluble in water at 25℃(0.5%), freely soluble in dilute acid and sodium hydroxide solution and insoluble in ethanol and ethyl ether. 
L-Aspartic Acid decomposes when heated to 270 ℃. 
L-Aspartic Acid's isoelectric point is 2.77 and its specific rotation is associated with the soluble solvent. 
L-Aspartic Acid is dextral in the acid solution and water solution, but levorotary in the alkali solution. 
Combined with HNO2, alcohol or acyl chloride, it can produce L- malic acid, ester and amide respectively. 
L-Aspartic Acid is the ingredient of unripe sugarcane and beet molasses.
L-Aspartic Acid (abbreviated as Asp or D) is an α-amino acid with the chemical formula HOOCCH(NH2 )CH2COOH. 

The carboxylate anion, salt, or ester of aspartic acid is known as aspartate. 
The Lisomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins.
L-Aspartic Acid's codons are GAU and GAC. 
Aspartic acid is, together with glutamic acid, classified as an acidic amino acid with a pKa of 3.9, however in a peptide the pKa is highly dependent on the local environment. 
A pKa as high as 14 is not at all uncommon. 
L-Aspartic Acid is pervasive in biosynthesis. 
As with all amino acids, the presence of acid protons depends on the residue's local chemical environment and the pH of the solution.
L-Aspartic Acid is an aliphatic monoaminodicarboxylic acid (amino acid) and is a well-known constituent of protein. 
Colorless crystals. 
Soluble in water; insoluble in alcohol and ether. 
Optically active. 

Uses    
L-Aspartic Acid is used as an electrolyte supplement for aminophenol transfusion, inorganic ion supplement (K+, Ca+, etc.) and fatigue restorer. 
Potassium magnesium aspartate injection or oral solution can be used for arrhythmia, premature beat, tachycardia, hypokalemia, hypomagnesemia, heart failure, myocardial infarction, angina pectoris, hepatitis, cirrhosis and other diseases caused by cardiac glycoside poisoning. 
Due to its low toxicity, L-Aspartic Acid cannot be injected without dilution, and the patients with renal insufficiency and atrioventricular conduction block should use it with caution.
L-Aspartic acid is used as a component of parenteral and enteral nutrition and as a pharmaceutical ingredient. 
L-Aspartic Acid is used for cell culture and in manufacturing processes. 
L-Aspartic Acid is widely utilized for mineral supplementation in the salt form.
L-Aspartic Acid is an amino acid used as a skin-conditioning agent.
L-Aspartic Acid is used as a dietary supplement, it can be blended with minerals to make compounds like potassium aspartate, copper aspartate, manganese aspartate, magnesium aspartate, zinc aspartate and more. 
Increasing the absorption, and hence utilization potentials, of these minerals via the addition of aspartate induces certain health benefits. 
Many athletes use L-Aspartic Acid-based mineral supplements orally to enhance their performance capacities. 
Aspartic acid and glutamic acid play important roles as general acids in enzyme active centers, as well as in maintaining the solubility and ionic character of proteins. 
L-Aspartic Acid can help promote a robust metabolism, and is sometimes used to treat fatigue and depression. 
L-Aspartic Acid is used as a component of parenteral and enteral nutrition. 
In pharmaceutical agents L-Aspartic Acid is used as an ammoniac detoxicating agent, hepar function accelerator and fatigue refresher.

Production    
L-Aspartic Acid is mainly produced by enzymatic method. 
L-Aspartic Acid acts on the fumaric acid and ammonia, that is, which generates L- aspartic acid.
Strain Culturing: Eschrichia coli Asl.881 was cultured. 
The common meat juice medium is agarslantculture-medium. 
The vase medium comprises corn steep liquor 7.5%, fumaric acid 2.0% and MgSO4 7H2O 0.02%. 
Adjust the pH value of solution to 6.0 with ammonia water, then put 50-100ml culture medium into 500ml cone bottle after boiling and filtering. 
Take the fresh cultivated seeds on the slope or in the liquid, inoculate culture medium in shake flask, shake overnight at 37℃, adjust pH to 5.0 with 1mol/L HCl after enlarging culture step by step to 1000-2000L, cool it to room temperature after keeping 45℃ for 1h, centrifuge in rotary supercentrifuge and collect the thallus including aspartase.
Immobilize aspartase: Make a bioreactor to take out 20kg E.Coli wet cell, suspend it in the culture supernatant after centrifugation in 80L (or 80L saline), keep it at 40℃ and then add 90L 12% gelatin solution and 1.0% glutaraldehyde solution, which should be held 40℃.  

Stir well, set aside to cool down and solidify, soak in 0.25% glutaraldehyde solution, hold 5℃ after an overnight, cut into small pieces ( 3-5 mm3) , soak in 0.25% glutaraldehyde solution at 5℃ for a night, take it out and elut with water, drain to obtain immobilized E.Coli containing aspartase and load it into filled bioreactor in reserve.
Conversion: The solution of 1 mol/L of ammonium fumarate (including 1mmol/L MgCl2, pH8.5) substrate, which keeps 37℃, flows through a bioreactor at a constant speed (SV) continuously in the case of controlling the maximum conversion rate over 95% and then the conversion solution is obtained.
Roughhew and refine:  Add 1 mol/L of HCl into the conversion solution gradually to adjust pH valkue to 2.8, place at 5℃ overnight for crystallizing, filter to prepare crystallization, drain after water washing, drying at 105℃ to obtain L- aspartic acid crude. 
Use dilute ammonia to recrystallize, dissolve into 15% solution (pH5.0) with ammonia, add 1% activated carbon, stir and fade for 1h when heat to 70℃, filter immediately to remove slag, cool the filtrate, hold 5℃ overnight for crystallizing, filter to get crystallization and obtain the L-Aspartic acid finished products after vacuum drying at 85℃.

Synthesis    
L-Aspartic Acid is non - essential in mammals, being produced from oxaloacetate by transamination. 
L-Aspartic Acid can also be generated from ornithine and citrulline in the urea cycle. 
In plants and microorganisms, aspartate is the precursor to several amino acids, including four that are essential for humans: methionine, threonine, isoleucine, and lysine. 
The conversion of aspartate to these other amino acids begins with reduction of aspartate to its "semi aldehyde," O2CCH(NH2)CH2CHO. 

Asparagine is derived from aspartate via trans amidation :
-O2CCH(NH2)CH2CO2 - + G C (O)NH3+ O2CCH(NH2)CH2CONH3+ + GC(O)O
(where GC(O)NH2 and GC(O)OH are glutamine and glutamic acid, respectively).
Enzymatically, aspartic acid is reversibly synthesized by a transamination reaction between oxaloacetic acid and glutamic acid in the presence of pyridoxal phosphate.

Biosynthesis
In the human body, aspartate is most frequently synthesized through the transamination of oxaloacetate. 
The biosynthesis of aspartate is facilitated by an aminotransferase enzyme: the transfer of an amine group from another molecule such as alanine or glutamine yields aspartate and an alpha-keto acid.

Chemical synthesis
Industrially, L-Aspartic Acid is produced by amination of fumarate catalyzed by L-aspartate ammonia-lyase.
Racemic aspartic acid can be synthesized from diethyl sodium phthalimidomalonate, (C6H4(CO)2NC(CO2Et)2).