L-Glutamic acid

Absorption

Absorbed from the lumen of the small intestine into the enterocytes.Absorption is efficient and occurs by an active transport mechanism.

Toxicity

Glutamate causes neuronal damage and eventual cell death, particularly when NMDA receptors are activated, High dosages of glutamic acid may include symptoms such as headaches and neurological problems.

Description

L-Glutamic acid, or L-2-aminopentanedioic acid, is a naturally occurring amino acid of plant and animal proteins. It has a very faint odor reminiscent of yeast or freshly baked bread. It has a mild, somewhat sweet, meat-like taste.
The average glutamic acid content of food proteins is 20 percent. Expressed as glutamic acid per 100 g of the edible portions, medium fat beef contains about 2.65 g of glutamic acid; whole liquid cow milk, 0.82 g; lean pork, 2.16 g; haddock, 2.32 g; peas, 5.58 g; soybeans, 7.01 g; commeal, 1.62 g; and whole grain wheat flour, 4.16 g. In addition, free glutamic acid is present in many vegetables, fish, and meats in small amounts (0. 005 to 0.23 g per 100 g) and as high as 2 g per 100 g in some varieties of cheese. Recent estimates of free amino acids in the milk of various species indicated that the free glutamic acid in human milk is about 0.22 g per 100 mL.
Glutamic acid and its salts are prepared commercially by hydrolysis of gluten (wheat, corn, soybean, sugarbeet protein); by fermentation from glucose-containing raw materials; the racemic acid may be resolved into the d- and ι-isomer by fractional crystallization; from 2 -cyclopentenylamine; by microbial conversion of aketoglutaric acid; or by an alternative method, using Bacillus megatherium-cereus; from fumaric acid using B. pumilus; from starch.
Glutamic acid and the hydrochloride as well as the mono-sodium, -potassium, and -ammonium salts of L-glutamic acid share similar physical properties: they are nearly odorless, white, free-flowing crystalline powders, and except for glutamic acid and glutamic acid hydrochloride, are freely soluble in water. Glutamic acid is slightly soluble and glutamic acid hydrochloride moderately soluble in water. The pH of a saturated solution is about 3.2.

Chemical properties

White cryst. powder

Chemical properties

L-Glutamic acid has a very faint odor reminiscent of yeast or freshly baked bread and a mild, somewhat sweet, meat- like taste This is a naturally occurring amino acid of plant and animal proteins The average glutamic acid content of food proteins is 20%, expressed as glutamic acid per 100 g of the edible portions For a detailed description, see Burdock (1997).

Occurrence

Reported as occurring in many vegetable proteins, in beef fbrin, in the chrysalis of silkworm, in the hydro- lysate of crystalline insulin Also present in other important peptides, such as glutathione, tyrocidin, folic acid, β-lactoglobulin, secretin and bacitracin, and in growth hormone

The Uses of L-Glutamic acid

Glutamic acid is an amino acid used to form proteins. In the body, it turns into glutamate.
This is a chemical that helps nerve cells in the brain send and receive information from other cells. It may be involved in learning and memory. It may help people with hypochlorhydria (low stomach acid) or achlorhydria (no stomach acid).  

The Uses of L-Glutamic acid

A non-essential amino acid. Its salt form (glutamate) is an important neurotransmitter that plays a key role in long-term potentiation and is important for learning and memory. It is also a key molecu le in cellular metabolism.

The Uses of L-Glutamic acid

Amino acid/exptl antieplileptic

Indications

Considered to be nature's "Brain food" by improving mental capacities; helps speed the healing of ulcers; gives a "lift" from fatigue; helps control alcoholism, schizophrenia and the craving for sugar.

Background

A peptide that is a homopolymer of glutamic acid.

Definition

ChEBI: An optically active form of glutamic acid having L-configuration.

Preparation

By hydrolysis of gluten (wheat, corn or other vegetable sources); by fermentation from glucose-containing raw materials; the racemic acid may be resolved into the d- and l-isomer by fractional crystallization; from 2-cyclopentenylamine; by microbial conversion of α-ketoglutaric acid; or by an alternative method, using Bacillus megatherium-cereus; from fumaric acid, using B pumilus; from starch.

Biotechnological Production

For industrial production of L-glutamic acid, molasses (sucrose), starch hydrolysates (glucose) and ammonium sulfate are generally used as carbon and nitrogen sources, respectively. Key factors in controlling the fermentation are the presence of biotin in optimal concentration – to optimize cell growth and the excretion of Lglutamate – and sufficient supply of oxygen to reduce the accumulation of byproducts, such as lactic and succinic acid. In biotin-rich fermentation media the addition of penicillin or cephalosporin C favors the overproduction of L-glutamic acid due to effects on the cell membrane. The supplementation of fatty acids also results in an increased permeability of the cells thus enhancing glutamate excretion.
A strain of Microbacterium ammoniaphilum cultured under biotin-deficient conditions produced 58 % of L-glutamic acid formed from glucose via phosphoenolpyruvate, citrate, and of a-ketoglutarate and the other 42 % via the tricarboxylic acid (TCA) or the glyoxylate cycle.

Biological Activity

The predominant excitatory transmitter in the mammalian central nervous system. Acts at ionotropic and metabotropic glutamate receptors.

Biochem/physiol Actions

L-Glutamic acid along with l-Lysine is used for preparation of bifunctional DTPA-like ligands. L-glutamic acid can stimulate the spontaneous release of [3H] dopamine ( [3H] DA).

Pharmacokinetics

In addition to being one of the building blocks in protein synthesis, it is the most widespread neurotransmitter in brain function, as an excitatory neurotransmitter and as a precursor for the synthesis of GABA in GABAergic neurons.

Safety Profile

Human systemic effects by ingestion and intravenous routes: headache and nausea or vomiting. When heated to decomposition it emits toxic fumes of NOx.

Metabolism

Hepatic

storage

Room temperature

Purification Methods

Crystallise L-glutamic acid from H2O acidified to pH 3.2 by adding 4volumes of EtOH, and drying at 110o. Likely impurities are aspartic acid and cysteine. It sublimes at 170-175o/10mm. It melts at 160o with cyclisation to L-pyrrolidone carboxylic acid. [Dunn & Brophy J Biol Chem 99 224 1958, Parikh et al. J Am Chem Soc 80 9571958, Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 pp 1929-1952 1961, Beilstein 4 III 1530, 4 IV 3028.]