A summary of the most common chemical descriptors (InChI Key and SMILES codes) for Proline are summarized together with 3D and 2D structures and relevant physico-chemical properties.

What is the Proline?

The molecule Proline presents a molecular formula of C5H9NO2 and its IUPAC name is (2S)-pyrrolidine-2-carboxylic acid.

Proline is a non-essential amino acid that belongs in proteins in the human body. It is classified as a hydroxyproline, which means that it contains a hydroxyl group (-OH) attached to the proline molecule. Proline is important for maintaining the structure and function of proteins, and it is involved in a number of processes in the body, including collagen synthesis, wound healing, and immune function..

Proline is synthesized in the body from the amino acid glutamic acid, and it can also be obtained from the diet through the consumption of protein-rich foods, such as meat, dairy products, and eggs. Proline belongs in high concentrations in collagen, which is the main structural protein in connective tissue, such as skin, tendons, and cartilage. Collagen is responsible for giving these tissues their strength and elasticity, and proline plays a key role in maintaining the proper structure of collagen fibers..

Proline is also involved in the synthesis of other proteins, such as elastin, which belongs in elastic fibers in the skin, blood vessels, and respiratory system. Elastin helps these tissues to stretch and bounce back to their original shape, and proline is important for maintaining the proper structure of elastin fibers..

In addition to its role in protein synthesis, proline is also involved in wound healing and immune function. It plays a role in the formation of new blood vessels during the healing process, and it is also involved in the production of antibodies, which are proteins that help to protect the body against infection..


From all the above, this molecule is an important amino acid that plays a key role in the structure and function of proteins in the body. It is essential for maintaining the proper structure of collagen and elastin fibers, and it is also involved in wound healing and immune function..

3D structure

Cartesian coordinates

Geometry of Proline in x, y and z coordinates (Å units) to copy/paste elsewhere. Generated with Open Babel software.

2D drawing


Proline ONIBWKKTOPOVIA-BYPYZUCNSA-N chemical compound 2D structure molecule svg


Molecule descriptors

IUPAC name(2S)-pyrrolidine-2-carboxylic acid
InChI codeInChI=1S/C5H9NO2/c7-5(8)4-2-1-3-6-4/h4,6H,1-3H2,(H,7,8)/t4-/m0/s1

Other names (synonyms)

IUPAC nomenclature provides a standardized method for naming chemical compounds. Although this system is widely used in chemistry, many chemical compounds have also other names commonly used in different contexts. These synonyms can come from a variety of sources and are used for a variety of purposes.

One common source of synonyms for chemical compounds is the common or trivial names, assigned on the basis of appearance, properties, or origin of the molecule.

Another source of synonyms are historical or obsolete names employed in the past, however replaced nowadays by more modern or standardized names.

In addition to common and historical names, chemical compounds may also have synonyms that are specific to a particular field or industry.

  • (-)-(S)-Proline
  • (-)-2-Pyrrolidinecarboxylate
  • (-)-2-Pyrrolidinecarboxylic acid
  • (-)-Proline
  • (-)-Proline (S)-2-Carboxypyrrolidine
  • (2S)-2-carboxypyrrolidine
  • (2S)-Pyrrolidin-2-carbonsalphaure
  • (2S)-proline
  • (2S)-pyrrolidin-1-ium-2-carboxylate
  • (2S)-pyrrolidine-2-carboxylic acid
  • (S) -pyrrolidine-2-carboxylic acid
  • (S)-(-)-PROLIN
  • (S)-(-)-Proline
  • (S)-(-)-Pyrrolidine-2-carboxylate
  • (S)-(-)-Pyrrolidine-2-carboxylic acid
  • (S)-2-Carboxypyrrolidine
  • (S)-2-Pyrralidinecarboxylate
  • (S)-2-Pyrralidinecarboxylic acid
  • (S)-2-Pyrrolidinecarboxylate
  • (S)-2-Pyrrolidinecarboxylic acid
  • (S)-Proline
  • (S)-Pyrrolidine-2-carboxylic acid
  • (s)-2-pyrrolidinecarboxylicaci
  • (s)-2-pyrrolidinecarboxylicacid
  • (s)-prolin
  • 147-85-3
  • 147P853
  • 2-Pyrrolidinecarboxylate
  • 2-Pyrrolidinecarboxylic acid, (S)-
  • 2-pyrrolidinecarboxylic acid
  • 37159-97-0
  • 3h-l-proline
  • 4305-67-3
  • 9DLQ4CIU6V
  • A01B5B63-CC3D-4796-A7B4-C2DE26A6FA93
  • AC-11190
  • AI3-26710
  • AM20080359
  • AS-10803
  • BB 0242381
  • BCP25292
  • BDBM50000100
  • C00148
  • CB 1707
  • CCG-214709
  • CS-W019861
  • Carboxypyrrolidine
  • D00035
  • DB-029981
  • DB00172
  • EC 205-702-2
  • F0001-2348
  • FEMA No. 3319
  • FEMA Number 3319
  • GTPL3314
  • H-Pro
  • H-Pro-2-Chlorotrityl Resin
  • H-Pro-OH
  • HSDB 1210
  • HY-Y0252
  • L-(-)-Proline
  • L-(2,3-3H)Proline
  • L-2-pyrrolidinecarboxylic acid
  • L-Pro-OH
  • L-Prolin
  • L-Proline (JP17)
  • L-Proline, labeled with carbon-14
  • L-Proline,(S)
  • L-Proline;
  • L-Pyrrolidine-2-carboxylic acid
  • L-alpha-Pyrrolidinecarboxylic acid
  • L-proline
  • M02947
  • MFCD00064318
  • NCGC00014017
  • NCGC00014017-02
  • NCGC00014017-03
  • NCGC00097126-01
  • NSC 46703
  • NSC-46703
  • NSC-760114
  • NSC760114
  • P0481
  • P17692
  • PRO (IUPAC abbreviation)
  • Pharmakon1600-01301007
  • Pro-OH
  • Proline
  • Proline (L-Proline)
  • Proline, L-
  • Prolinum
  • Q-201327
  • Q20035886
  • Z1245635771
  • bmse000047
  • bmse000947
  • femanumber3319
  • prolina
  • proline
  • pyrrolidin-2-(S)-carboxylic acid
  • pyrrolidine-2-(S)-carboxylic acid
  • rac-proline
  • racemic proline
  • s-proline
  • s5629

Reference codes for other databases

There exist several different chemical codes commonly used in orded to identify molecules:
  • ZINC895360
  • AKOS010372120
  • AKOS015856025
  • DTXSID5044021
  • CHEMBL54922
  • CHEBI:17203
  • EINECS 205-702-2
  • SCHEMBL7792

Physico-Chemical properties

IUPAC name(2S)-pyrrolidine-2-carboxylic acid
Molecular formulaC5H9NO2
Molecular weight115.13
Melting point (ºC)
Boiling point (ºC)
Density (g/cm3)
Molar refractivity32.52
Topological polar surface area49.3

LogP and topological polar surface area (TPSA) values were estimated using Open Babel software.

The n-octanol/water partition coeficient (Kow) data is applied in toxicology and drug research. Kow values are used, to guess the environmental fate of persistent organic pollutants. High partition coefficients values, tend to accumulate in the fatty tissue of organisms. Molecules with a log(Kow) (or LogP) greater than 5 are considered to bioaccumulate.

TPSA values are the sum of the surface area over all polar atoms or molecules, mainly oxygen and nitrogen, also including hydrogen atoms.

In medicinal chemistry, TPSA is used to assess the ability of a drug to permeabilise cells.

For molecules to penetrate the blood-brain barrier (and act on receptors in the central nervous system), TPSA values below 90 Å2 are required. Thus, molecules with a polar surface area greater than 140 Å2 tend to be poorly permeable to cell membranes.