Crystal system Orthorhombic system. Alpha-form and beta-form exist depending on crystallization conditions.
Melting point 247¡ãC(decomposition)
Specific rotation = +31.8¡ã ~ +32.2¡ã(2N HCl,c=10)
Dissociation constant pKCOOH=2.19 pKCOOH=4.25 pKNH3+=9.67 pI=3.22
Solubility (H2O,g/dl) 0.34(0¡ã), 0.50(10¡ã), 0.72(20¡ã), 1.04(30¡ã), 1.51(40¡ã), 2.19(50¡ã), 3.17(60¡ã), 4.59(70¡ã), 6.66(80¡ã), 9.66(90¡ã), 14.00(100¡ã)
Stability Stable in the crystalline state. A ring-closure occurs by heating at above 160qjC to form L-pyrrolidone carboxylic acid even in its crystalline state, accompanying racemisation at above 190q?222qjC. Cyclisation also occurs in an aqueous solution. In an acidic medium, the rate of cyclisation is high but the equilibrium constant is small, while in a neutral medium, the rate of this reaction is low and the equilibrium constant is larger.
Derivatives Acetyl-L-Glutamic acid : mp 200¡ãC
Benzoyl-L-Glutamic acid : mp 137¡ãC
Carbobenzoxy-L-Glutamic acid : mp 118¡ãC
L-Glutamic acid diethylester hydrochloride : mp 113¡ãC
As Barium salts and Zinc salts of L-Glutamic acid are hardly soluble in water, they are used for separation of L-Glutamic acid. Monosodium salt is important as a flavoring material.
Metabolism Glycogenic. By deamination, L-Glutamic acid is converted to alpha-ketoglutaric acid which is an important component in the TCA cycle, and is converted to glycogen via succinic acid, fumaric acid, malic acid, oxaloacetic acid and pyruvic acid. It undergoes a reciprocal conversion with L-Proline via L-Glutamic acid-gamma-semialdehyde. L-Glutamic acid occupies a central position in the amino acid metabolism pathway as a key material in the transamination, and also it is deeply involved in the metabolism of suger and fatty acid. Also, by reciprocal conversion with L-Glutamine, it controls the storage and excretion of ammonia. In the brain, it plays an important role as a neurotransmitter and in potassium transport and in the detoxification of ammonia. Recently numerous gamma-glutamyl peptides have been discovered in the brain such as Glutathione (gamma-L-glutamyl-L-cysteinyl-glycine), which is involved in oxidation-reduction in vivo.
Glutamic acid is required for
It is an important excitatory neurotransmitter, and glutamic acid is also important in the metabolism of sugars and fats.
It helps with the transportation of potassium across the blood-brain barrier, although itself does not pass this barrier that easily. It also shows promise in the future treatment of neurological conditions, ulcers, hypoglycemic come, muscular dystrophy, epilepsy, Parkinson's, and mental retardation.
Glutamic acid can be used as fuel in the brain, and can attach itself to nitrogen atoms in the process of forming glutamine, and this action also detoxifies the body of ammonia. This action is the only way in which the brain can be detoxified from ammonia.
The fluid produced by the prostate gland also contains amounts of glutamic acid, and may play a role in the normal function of the prostate.
Deficiency of glutamic acid
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Toxicity and symptoms of high intake
High dosages of glutamic acid may include symptoms such as headaches and neurological problems.
Although no major side effects are reported on supplementation of this nutrient, people with kidney or liver disease should not consume high intakes of amino acids without first consulting a medical professional.
People suffering from personality disorders as well as child behavior disorders may find benefit from this nutrient.
Food sources of glutamic acid
Excellent sources of glutamic acid include meat, poultry, fish, eggs, and dairy products, as well as some protein-rich plant foods.