Proline, L-Proline, 147-85-3

Proline, L-Proline, 147-85-3

L-PROLINE TECHNICAL DATA SHEET (TDS)

Chemical Name: L-Proline / L-Proline / (S)-Pyrrolidine-2-carboxylic acid
CAS Number: 147-85-3
EC Number: 205-702-2

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

CHEMICAL STRUCTURE AND EXPLANATION:

L-Proline has a unique structure among the 20 standard amino acids found in nature. Unlike other amino acids, its α-amino group (-NH₂) is bonded to the side chain, forming a 5-membered pyrrolidine ring. This structural feature technically classifies L-Proline as an "imino acid" (a secondary amine).

Structural Formula (Open Structure):

        O
        ||
       C - OH
      /
     HC - NH
    /       \
   H₂C       CH₂
    \       /
     C —— C
     H   H

(Pyrrolidine ring, carboxyl group, and secondary amine group forming the cyclic structure)

3D (Stereochemical) Representation:
L-Proline is a chiral molecule, and its natural form is the L-(S) configuration. This is confirmed by its specific optical rotation value: [α]20D=−84.0to−86.0°[α]20D=−84.0to−86.0°.

Significance of the Structure:

• This rigid ring structure causes turns and bends in protein chains.

• It plays a critical role in stabilizing the triple helix structure of collagen.

• This structure affects protein folding and conformation differently from other amino acids.

L-Proline is one of the 20 standard amino acids that make up proteins. It is the only cyclic amino acid found in nature, possessing a unique structure where the α-amino group bonds to the side chain to form a ring. Therefore, it is technically classified as an "imino acid." It is a non-essential amino acid as it can be synthesized in the body from L-glutamic acid. It is a key component of collagen and plays a critical role in joint, tendon, connective tissue, and skin health. It is also widely used in cell culture media, as a stabilizer in pharmaceutical formulations, and in the development of biological drugs.

2. PHYSICAL AND CHEMICAL PROPERTIES

L-Proline has exceptionally high solubility in water (1623 g/L at 25°C). It decomposes upon melting at 220-228°C. Its aqueous solution is neutral to slightly acidic (pH 5-7). Its specific optical rotation ranges from -84.0 to -86.0°, confirming the L-configuration. It has a very low LogP value, indicating it is highly hydrophilic and has low bioaccumulation potential.

3. SOLUBILITY PROFILE

L-Proline has exceptionally high solubility in water; it can dissolve up to 1623 g/L at 25°C. Its solubility increases further with temperature (239 g/100 mL at 65°C). It shows limited solubility in ethyl alcohol (1.55% at 35°C). It is insoluble in organic solvents such as ether, butanol, and isopropanol.

4. CHEMICAL PROPERTIES AND REACTIONS

Unlike other amino acids, L-Proline contains a five-membered ring (pyrrolidine ring) formed by the bonding of the α-amino group to the side chain. For this reason, it is technically classified as an "imino acid." This rigid ring structure causes turns and bends in the secondary structure of proteins, affecting protein conformation and folding. Proline plays a critical role in stabilizing the triple helix structure of collagen. Additionally, it exhibits "compatible osmolyte" properties, enhancing protein stability under thermal, mechanical, and freeze-thaw stress.

5. SPECIFICATIONS (PHARMACEUTICAL GRADE)

L-Proline is manufactured in pharmaceutical quality compliant with various pharmacopoeias (USP, EP, BP, JP, ChP). It is available in high purity and low endotoxin levels, making it suitable for parenteral formulations and biological drug production. Manufacturers like Pfanstiehl produce under cGMP conditions, ensuring high purity and batch-to-batch consistency.

6. APPLICATIONS AND INDUSTRIAL USES

6.1. Biopharmaceutical and Drug Formulations (Most Important Application)

L-Proline is particularly valuable in the biopharmaceutical industry. High-purity L-Proline, provided by manufacturers like Pfanstiehl, is used as a stabilizer in formulations of monoclonal antibodies, recombinant enzymes, and fusion proteins. Its compatible osmolyte properties stabilize the native folded state of proteins and reduce aggregation pathways.

6.2. Cell Culture and Biotechnology

L-Proline is an important component of cell culture media and is found in MEM (Minimum Essential Medium) non-essential amino acid solution. CELLPURE® grade is specifically manufactured for cell culture and biochemistry applications.

6.3. Food and Nutrition

L-Proline is used in the food industry as a flavoring and sweetening agent with FEMA number 3319. It is also used as a dietary supplement and to increase the nutritional value of foods.

6.4. Cosmetics and Personal Care

L-Proline improves skin health by supporting collagen synthesis. It is used in anti-aging formulations and skin care products as a moisturizer and texture enhancer.

6.5. Chemical Synthesis and Catalysis

L-Proline is also used as an asymmetric catalyst in organic synthesis. It is an effective catalyst in asymmetric aldol cyclizations and Michael additions.

7. BIOLOGICAL AND STRUCTURAL PROPERTIES

Unlike other amino acids, L-Proline contains a five-membered ring (pyrrolidine ring) formed by the bonding of the α-amino group to the side chain. Therefore, it is technically classified as an "imino acid." This rigid ring structure causes turns and bends in the secondary structure of proteins, affecting protein conformation and folding. Proline plays a critical role in stabilizing the triple helix structure of collagen. Additionally, it protects cells against osmotic stress due to its cellular osmoprotectant properties.

8. BIOCHEMICAL APPLICATIONS

L-Proline is used as a non-essential amino acid source in cell culture media. It is also widely used in protein research, metabolomics, and microbiological studies.

9. SAFETY AND TOXICOLOGY

L-Proline is not classified as a hazardous substance. It has low toxicity (oral LD50 > 5110 mg/kg). It does not cause skin irritation but may cause mild eye irritation. It has no mutagenic, carcinogenic, or reproductive toxicity classification. It has low environmental bioaccumulation potential. It is classified as WGK 1 (slight hazard to water).

10. TRANSPORT INFORMATION

L-Proline is not classified as a hazardous substance. There are no special restrictions for its transport by sea, land, or air.

11. REGULATORY INFORMATION

L-Proline is registered in all major industrial markets, including the EU, USA, Canada, Australia, Japan, Korea, and China. Pharmaceutical-grade products are compliant with USP, EP, BP, JP, and ChP pharmacopoeias. It is considered GRAS (Generally Recognized As Safe) by the FDA.

12. STORAGE AND HANDLING

L-Proline should be stored at 2-25°C in a cool, dry, and well-ventilated area. It must be kept in tightly closed containers. It should be kept away from strong oxidizers. The shelf life is 24 months under proper storage conditions.

Handling Notes:

• Avoid dust formation (use closed systems, local exhaust ventilation)

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

• Avoid inhaling dust (use dust mask or respirator)

• Keep away from ignition sources

13. FIREFIGHTING MEASURES

L-Proline may burn at high temperatures. In case of fire, use water spray, CO₂, or dry chemical powder for extinguishing. Thermal decomposition produces toxic and irritating fumes (nitrogen oxides, carbon monoxide, carbon dioxide). Firefighters should use a self-contained breathing apparatus (SCBA) and full protective clothing.

14. ACCIDENTAL RELEASE MEASURES

In case of a spill, wear appropriate personal protective equipment. Contain the spill to prevent dust spread. Clean up using a vacuum or by careful sweeping and place in an appropriate disposal container. Prevent environmental release and dispose of waste according to local regulations.

15. FIRST AID MEASURES

Standard first aid measures apply for L-Proline exposure. In case of inhalation, move to fresh air. In case of skin contact, wash with plenty of soap and water. In case of eye contact, rinse with plenty of water for at least 15 minutes. In case of ingestion, do not induce vomiting; drink plenty of water.

16. RAW MATERIALS AND DOWNSTREAM PRODUCTS

16.1. Raw Materials (Upstream)

16.2. Downstream Products

17. SECTORAL SUITABILITY AND USAGE LEVELS

18. CARBON DIOXIDE ABSORPTION AND REAGENTS

L-Proline is also used in carbon dioxide (CO₂) absorption and chemical reactions. Proline can be used as a reagent to absorb CO₂. Additionally, its derivatives, such as "proline-based carbamate ionic liquids" and "prolinate amino acid ionic liquids," are used in CO₂ capture applications. These derivatives of proline have the capacity to chemically absorb CO₂. This property stems from the secondary amine (-NH-) group in its structure, which can form carbamates with CO₂.

19. DERIVATIVES AND RELATED COMPOUNDS

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY:
L-Proline (C₅H₉NO₂, CAS 147-85-3) is one of the 20 standard amino acids that make up proteins. It is the only cyclic amino acid found in nature, forming a 5-membered pyrrolidine ring by bonding the α-amino group to the side chain, which technically classifies it as an "imino acid." This unique structure causes turns and bends in protein secondary structures and plays a critical role in stabilizing the triple helix structure of collagen.

It appears as a white crystalline powder or colorless crystals, is odorless, and has a sweet taste. Its molecular weight is 115.13 g/mol, and its solubility in water is 1623 g/L at 25°C (very high). Its melting point is 220-228°C, at which it decomposes. It is a non-essential amino acid, synthesized in the body from L-glutamic acid. It plays a critical role in collagen stability, connective tissue integrity, and joint health. Its most important application is as a protein stabilizer and formulation excipient in the biopharmaceutical industry. It is also used in cell culture media, as a dietary supplement and flavoring agent in the food industry, in cosmetic products, and as an asymmetric catalyst in organic synthesis. It has low toxicity and is not classified as a hazardous substance. It should be stored in a cool, dry, and well-ventilated area at 2-25°C. Its shelf life is 24 months.

Key Properties:

Main Application Areas:

Key Safety Points:

• LOW TOXICITY: Not a hazardous substance; LD50 > 5110 mg/kg

• NON-IRRITANT: No skin irritation; may cause mild eye irritation

• NON-MUTAGENIC: No carcinogenic classification

• STORAGE: 2-25°C, cool, dry, tightly closed

• PPE RECOMMENDED: Dust mask, safety goggles, nitrile gloves

• INCOMPATIBLE: Strong oxidizers

CRITICAL WARNINGS:

• L-Proline is the only cyclic amino acid found in nature and is technically classified as an "imino acid." This structure results from the α-amino group (NH₂) bonding to the side chain to form a 5-membered pyrrolidine ring.

• This unique structure causes turns and bends in protein chains and plays a critical role in stabilizing the triple helix structure of collagen.

• In the biopharmaceutical industry, L-Proline is used as a high-purity (USP, EP, BP, JP, ChP compliant) protein stabilizer, protecting proteins against thermal, mechanical, and freeze-thaw stress.

• It is a component of MEM non-essential amino acid solution in cell culture media.

• It is a non-essential amino acid; the body can synthesize it from L-glutamic acid.

• It is a key component of collagen and plays a critical role in joint, tendon, connective tissue, and skin health.

• It is used as a flavoring agent in the food industry with FEMA number 3319.

• It is used as an asymmetric catalyst in organic synthesis for aldol and Michael reactions.

• Its high water solubility (1623 g/L at 25°C) makes it ideal for aqueous formulations.

• Pharmaceutical-grade L-Proline is produced under cGMP conditions, ensuring low endotoxin and metal levels with batch-to-batch consistency.

• Due to the secondary amine (-NH-) group in its structure, L-Proline can form carbamates with CO₂ and is therefore used in the production of proline-based ionic liquids for CO₂ absorption.

• Due to its very high solubility in water, it is suitable for high-concentration formulations.

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 applications 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-Proline.