L-Proline

Proline is the second amino acid to be obtained synthetically before its presence as a product of the hydrolysis of the protein molecule was recognized. It was first prepared in 1900 by Willstatter, who was interested in the position of the carboxyl group in N-methylproline. A year later, Fischer published a synthesis of proline from phthalimide propylmalonic ester.

Proline was first isolated from a protein by Fischer in 1901. He hydrolyzed casein with hydrochloric acid, esterified the amino acids and distilled the esters.

IUPAC Name: (2S)-Pyrrolidine-2-carboxylic acid
Symbol: Pro or P
Molecular Weight: 115.13046 g/mol
Molecular Formula: C5H9NO2
Canonical SMILES: C1CC(NC1)C(=O)O
Isomeric SMILES: C1C[C@H](NC1)C(=O)O
InChIKey Identifier: ONIBWKKTOPOVIA-XWEZEGGSDT
CAS Number: 147-85-3
MDL Number: MFCD00064318
Melting point: 228 °C
Solubility in water: 1623 g/L (25 °C)
2D Molfile: Get the molfile
3D PDB file: Get the PDB file
Other names: 2-Pyrrolidinecarboxylic acid; (S)-Pyrrolidine-2-carboxylic acid

Load 3D Structure of Proline

L-Proline is an essential component of collagen and is important for proper functioning of joints and tendons. Also helps maintain and strengthen heart muscles.

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