Glutamic Acid, L-Glutamic Acid, L-Glutamine Acid, H-Glu-OH, Glu, 56-86-0

L-GLUTAMIC ACID

L-Glutamic Acid / Glutamic Acid / (S)-2-Aminopentanedioic acid / Glu
CAS Number: 56-86-0
EC Number: 200-293-7

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

L-Glutamic acid is a non-essential, acidic amino acid that is one of the 20 standard amino acids used in protein synthesis. It is the most abundant excitatory neurotransmitter in the mammalian central nervous system, playing a critical role in brain function, learning, and memory. L-Glutamic acid is a key intermediate in cellular metabolism, particularly in the citric acid cycle (as α-ketoglutarate). It is also the precursor to γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain. L-Glutamic acid appears as white or colorless scaly crystals or crystalline powder, is odorless, and has a slightly special taste with a sour note. It is slightly soluble in cold water, soluble in hot water, and insoluble in ethanol, ether, and acetone. L-Glutamic acid is widely used in the food industry as a flavor enhancer (as monosodium glutamate - MSG), in pharmaceuticals for hepatic coma treatment, as a nutritional supplement, and in biochemical research. It was first discovered by Rithausen in 1866 through the acid hydrolysis of wheat gluten.

2. PHYSICAL AND CHEMICAL PROPERTIES

L-Glutamic acid is a white or colorless crystalline powder or scaly crystals. It has a density of 1.54 g/cm³ at 20°C. The melting point is approximately 205°C with decomposition, and it sublimes at approximately 200°C. It is slightly soluble in cold water (7.5 g/L at 20°C), soluble in hot water, and insoluble in ethanol, ether, and acetone. The pH of an 8.6 g/L aqueous solution at 25°C is 3.0-3.5, indicating acidic character. The specific optical rotation is +32.0° (c=10, 2N HCl). The pKa values are 2.13 (carboxyl group), 4.32 (side chain carboxyl group), and 9.47 (amino group). The isoelectric point is 3.22.

3. CHEMICAL PROPERTIES AND REACTIONS

L-Glutamic acid is an acidic amino acid with two carboxyl groups and one amino group. This unique structure gives L-glutamic acid its distinctive chemical properties and biological activities.

Acid-Base Properties:

L-Glutamic acid has two carboxyl groups (COOH) and one amino group (NH₂). pKa values: 2.13 (pK1), 4.32 (pK2, side chain), and 9.47 (pK3).

Salt Formation:

L-Glutamic acid forms salts with bases. The most important salt is monosodium glutamate (MSG, sodium glutamate), which is widely used as a flavor enhancer in the food industry.

L-Glutamic Acid + NaOH → Sodium Glutamate (MSG) + H₂O

Esterification:

L-Glutamic acid can be esterified with alcohols to form glutamic acid esters for pharmaceutical intermediates.

Decarboxylation:

L-Glutamic acid can be decarboxylated by the enzyme glutamate decarboxylase (GAD) to form γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain.

Transamination:

L-Glutamic acid participates in transamination reactions, transferring its amino group to α-ketoglutarate to form aspartate and oxaloacetate (or other amino acids).

Deamination:

L-Glutamic acid can be deaminated by glutamate dehydrogenase (GDH) to form α-ketoglutarate and ammonia, linking amino acid metabolism to the citric acid cycle.

Thermal Decomposition:

Above its melting point, L-glutamic acid decomposes, producing ammonia, carbon dioxide, and various nitrogen-containing compounds.

4. PRODUCTION METHODS

L-Glutamic acid is produced industrially primarily through microbial fermentation using sugars as raw materials.

Detailed Production Process (Fermentation Method - Most Common):

1. Medium Preparation: Sugars (molasses or starch hydrolysates) are prepared as the carbon source, urea as the nitrogen source, along with mineral salts and nutrients (corn steep liquor for biotin and organic nitrogen).

2. Fermentation: Corynebacterium glutamicum or Brevibacterium species are cultivated in large fermenters with aeration and agitation at 30-34°C, pH 7-8, for 30-40 hours.

3. Cell Separation: Microbial cells are separated from the fermentation broth by filtration or centrifugation.

4. Isoelectric Point Extraction: The pH of the fermentation broth is adjusted to 3.0 (the isoelectric point of glutamic acid) using hydrochloric acid. L-Glutamic acid precipitates as crystals.

5. Crystallization and Separation: The precipitated L-glutamic acid crystals are separated by filtration.

6. Mother Liquor Extraction: Glutamic acid remaining in the mother liquor is further extracted using 732 ion exchange resin.

7. Drying: The crystals are dried to reduce moisture content.

8. Milling and Packaging: The dried crystals are milled to the desired particle size and packaged in 25 kg bags.

5. PHYSIOLOGICAL FUNCTIONS AND HEALTH BENEFITS

L-Glutamic acid is a non-essential amino acid that plays numerous critical roles in the body. It is involved in protein synthesis, neurotransmission, ammonia detoxification, and energy metabolism.

5.1. Neurotransmission (Excitatory Neurotransmitter)

L-Glutamic acid is the most abundant excitatory neurotransmitter in the mammalian central nervous system, playing a critical role in learning, memory, and synaptic plasticity. It is also the precursor to γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter, helping to maintain balance in the brain.

5.2. Ammonia Detoxification (Hepatic Coma Treatment)

L-Glutamic acid combines with ammonia in the blood to form non-toxic glutamine, which is then excreted by the kidneys. This reduces blood ammonia levels and is used in the treatment of hepatic coma and severe liver dysfunction.

5.3. Energy Metabolism

L-Glutamic acid is a key intermediate in cellular metabolism, particularly in the citric acid cycle (as α-ketoglutarate). It is also a precursor to glutathione, a major antioxidant, and is involved in the synthesis of glutamine, proline, arginine, and lysine.

6. APPLICATIONS AND INDUSTRIAL USES

L-Glutamic acid has a wide range of applications in the food industry, pharmaceuticals, animal nutrition, and biochemical research.

6.1. Food Industry (Flavor Enhancer - Most Important Application)

L-Glutamic acid's most important application is in the production of monosodium glutamate (MSG), one of the most widely used flavor enhancers in the world. It is also used as a flavor enhancer, salt substitute, and nutritional supplement in soups, broths, seasonings, meat products, and seafood canned products.

6.2. Pharmaceutical Applications

L-Glutamic acid is used in pharmaceutical applications for the treatment of hepatic coma, hepatic encephalopathy, and severe liver dysfunction. It is also used as an adjuvant therapy for schizophrenia, epilepsy, and other neurological disorders.

6.3. Biochemical Research

6.4. Animal Nutrition

7. DOSAGE AND ADMINISTRATION

8. POTENTIAL SIDE EFFECTS AND WARNINGS

9. DRUG INTERACTIONS

10. NATURAL FOOD SOURCES OF L-GLUTAMIC ACID

11. SAFETY AND TOXICOLOGY

12. FIRST AID MEASURES

13. SAFETY INFORMATION (GHS CLASSIFICATION)

Signal Word: WARNING

Hazard Statements (H-Codes):

Precautionary Statements (P-Codes):

14. FIREFIGHTING MEASURES

15. ACCIDENTAL RELEASE MEASURES

16. STORAGE AND HANDLING

L-Glutamic acid should be stored at 2-8°C in cool, dry, well-ventilated areas, protected from light and moisture. It is hygroscopic and should be protected from moisture. Containers should be kept tightly closed to prevent moisture absorption and contamination. Shelf life under proper storage conditions is typically 24-36 months.

Handling Notes:

• Avoid dust generation (use enclosed systems, local exhaust ventilation)

• Avoid contact with skin and eyes (use protective gloves and goggles)

• Avoid breathing dust (use dust mask or respirator)

• Keep away from ignition sources

• Do not allow material to become wet (hygroscopic)

17. TRANSPORT INFORMATION

L-Glutamic acid is not classified as a dangerous good for transport. It is shipped in 25 kg bags, drums, or FIBCs. During transport, protect from moisture, impact, and excessive heat.

18. REGULATORY INFORMATION

Regulatory Status:

19. OTHER NAMES AND DATABASE IDENTIFIERS

Database Identifiers:

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

L-Glutamic acid (C₅H₉NO₄, CAS 56-86-0) is a non-essential, acidic amino acid that is one of the 20 standard amino acids used in protein synthesis. It appears as white or colorless scaly crystals or crystalline powder, is odorless, and has a slightly special taste with a sour note. The molecular weight is 147.13 g/mol, density is 1.54 g/cm³ at 20°C, and melting point is 205°C (decomposes). It is slightly soluble in cold water (7.5 g/L at 20°C), soluble in hot water, and insoluble in ethanol, ether, and acetone. It is produced primarily through microbial fermentation using molasses or starch hydrolysates with Corynebacterium glutamicum or Brevibacterium species. L-Glutamic acid is the most abundant excitatory neurotransmitter in the mammalian central nervous system, playing a critical role in learning, memory, and synaptic plasticity. It is also the precursor to GABA, the main inhibitory neurotransmitter, and is involved in ammonia detoxification and energy metabolism. Its most important application is in the production of monosodium glutamate (MSG), one of the most widely used flavor enhancers in the world. It is also used in pharmaceuticals for the treatment of hepatic coma, hepatic encephalopathy, and severe liver dysfunction, as a nutritional supplement, and in biochemical research. It is considered GRAS by the FDA. It is stored at 2-8°C in cool, dry, well-ventilated areas, protected from light and moisture.

Key Properties:

Major Application Areas:

Key Safety Points:

• VERY LOW TOXICITY: GRAS by FDA; LD50 > 30,000 mg/kg (Rabbit)

• HYGROSCOPIC: Easily absorbing moisture; protect from moisture; store in tightly closed containers

• MILD IRRITANT: May cause mild skin and eye irritation

• STORAGE: Store at 2-8°C in cool, dry, well-ventilated area, protected from light and moisture

• PPE RECOMMENDED: Dust mask, safety goggles, protective gloves (for handling powder)

• SIDE EFFECTS: May cause headache in some individuals (MSG sensitivity); gastrointestinal distress at high doses

• FOOD ADDITIVE: Approved as flavor enhancer and nutritional supplement in many countries

CRITICAL WARNINGS:

Flavor Enhancer (MSG): L-Glutamic acid's most important application is in the production of monosodium glutamate (MSG), one of the most widely used flavor enhancers in the world. MSG enhances the savory umami taste in foods. It is used in soups, broths, seasonings, meat products, and processed foods. According to China's GB 2760-96 regulations, it can be used as a flavoring agent. The FDA has approved it as GRAS (21 CFR 182.1045). FAO/WHO permits its use up to 10 g/kg in soups and convenience foods.

Neurotransmitter: L-Glutamic acid is the most abundant excitatory neurotransmitter in the mammalian central nervous system, playing a critical role in learning, memory, and synaptic plasticity. It is also the precursor to γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain, helping to maintain balance in the central nervous system.

Hepatic Coma Treatment: L-Glutamic acid combines with ammonia in the blood to form non-toxic glutamine, which reduces blood ammonia levels. This makes it useful in the treatment of hepatic coma, hepatic encephalopathy, and severe liver dysfunction. Typical dosage for hepatic coma treatment is 2.5-5 g, 4 times daily under medical supervision.

Synthesis of Other Amino Acids: L-Glutamic acid is an important precursor for the synthesis of glutamine, proline, arginine, and lysine. It is also involved in the synthesis of glutathione (with glycine and cysteine), a major antioxidant.

Glutamate Dehydrogenase: L-Glutamic acid is involved in glutamate dehydrogenase-centered co-deamination reactions. It is also involved in the glucose-alanine cycle pathway, where it helps transport ammonia from muscle to the liver.

Ornithine Cycle (Urea Synthesis): In the ornithine cycle, glutamate dehydrogenase in mitochondria removes the amino group of glutamic acid, providing free ammonia for the synthesis of carbamoyl phosphate. Glutamate transaminase in the cytoplasm transfers the amino group of glutamic acid to oxaloacetic acid, which then forms aspartic acid, indirectly providing a second amino group for the cycle.

MSG Sensitivity: Some individuals may experience "MSG symptom complex" (headache, flushing, sweating, numbness) after consuming foods containing MSG. This is more common in sensitive individuals and at high doses. However, numerous studies have shown that MSG is safe for the general population at normal consumption levels.

Natural Sources: L-Glutamic acid is naturally found in protein-rich foods including meat, fish, eggs, dairy products, wheat gluten, soybeans, tomatoes, seaweed (kelp), mushrooms, and green peas. It is one of the most abundant amino acids in the diet.

Pregnancy and Lactation: L-Glutamic acid is generally considered safe during pregnancy and lactation at recommended doses. However, as with all supplements, it is recommended to consult a healthcare professional before use.

Packaging and Storage: L-Glutamic acid is typically packaged in 25 kg plastic bags, nylon bags, or plastic woven bags. During storage and transport, attention should be paid to moisture protection, sun protection, and low temperature storage.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. The information provided is based on available data and is believed to be accurate. However, the user is solely responsible for determining the suitability of the product for their specific application and for complying with all applicable regulations and safety requirements. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are responsible for testing the product in their own processes and applications. All local, national, and international regulations must be followed when working with L-glutamic acid.