L

L-Proline

IUPAC: (2S)-pyrrolidine-2-carboxylic acid

C5H9NO2 Organic Compounds CAS 147-85-3
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Quick Reference
Formula / NotationC5H9NO2
CAS Number147-85-3
Molecular Weight115.13
Melting Point221 dec °C
Density1.064 at 24 °C
Solubility162000 mg/L (at 25 °C)
AppearanceDry Powder
Also Known As(2S)-pyrrolidine-2-carboxylic acid; 147-85-3; proline; L-(-)-Proline; (S)-Pyrrolidine-2-carboxylic acid; (-)-Proline; 2-pyrrolidinecarboxylic acid; (-)-(S)-Proline; (S)-2-Pyrrolidinecarboxylic acid; prolina
CategoryOrganic Compounds

What is L-Proline?

L-proline is pyrrolidine in which the pro-S hydrogen at position 2 is substituted by a carboxylic acid group. L-Proline is the only one of the twenty DNA-encoded amino acids which has a secondary amino group alpha to the carboxyl group. It is an essential component of collagen and is important for proper functioning of joints and tendons. It also helps maintain and strengthen heart muscles. It has a role as a member of compatible osmolytes, a micronutrient, a nutraceutical, a mouse metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and an algal metabolite. It is a L-alpha-amino acid, a glutamine family amino acid, a proline and a proteinogenic amino acid. It is a conjugate base of a L-prolinium. It is a conjugate acid of a L-prolinate. It is an enantiomer of a D-proline. It is a tautomer of a L-proline zwitterion.

Formula & Notation

C5H9NO2

IUPAC Name: (2S)-pyrrolidine-2-carboxylic acid

Other Names / Synonyms: (2S)-pyrrolidine-2-carboxylic acid; 147-85-3; proline; L-(-)-Proline; (S)-Pyrrolidine-2-carboxylic acid; (-)-Proline; 2-pyrrolidinecarboxylic acid; (-)-(S)-Proline; (S)-2-Pyrrolidinecarboxylic acid; prolina

Properties & Characteristics

Appearance: Dry Powder. Molecular formula: C5H9NO2. Molecular weight: 115.13 g/mol. Melting point: 221 dec °C. Density: 1.064 at 24 °C. Solubility: 162000 mg/L (at 25 °C). LogP: -2.5.

Physical Data

PropertyValue
Melting Point221 dec °C
Density1.064 at 24 °C
Molecular Weight115.13
Solubility162000 mg/L (at 25 °C)
AppearanceDry Powder

Uses & Applications

Used as an industrial feedstock, solvent, pharmaceutical intermediate, flavoring agent, or chemical building block.

Safety Information

Flammable or irritant. Many organic compounds are flammable liquids or vapours. Keep away from ignition sources. Consult SDS for specific hazard data.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term L-Proline
Formula C5H9NO2
CAS Number 147-85-3
Molecular Weight 115.13
Synonyms (2S)-pyrrolidine-2-carboxylic acid; 147-85-3; proline; L-(-)-Proline; (S)-Pyrrolidine-2-carboxylic acid; (-)-Proline; 2-pyrrolidinecarboxylic acid; (-)-(S)-Proline; (S)-2-Pyrrolidinecarboxylic acid; prolina

Frequently Asked Questions

L-proline is pyrrolidine in which the pro-S hydrogen at position 2 is substituted by a carboxylic acid group. L-Proline is the only one of the twenty DNA-encoded amino acids which has a secondary amino group alpha to the carboxyl group. It is an essential component of collagen and is important for proper functioning of joints and tendons. It also helps maintain and strengthen heart muscles. It has a role as a member of compatible osmolytes, a micronutrient, a nutraceutical, a mouse metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and an algal metabolite. It is a L-alpha-amino acid, a glutamine family amino acid, a proline and a proteinogenic amino acid. It is a conjugate base of a L-prolinium. It is a conjugate acid of a L-prolinate. It is an enantiomer of a D-proline. It is a tautomer of a L-proline zwitterion.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.