Record Information
Creation date2015-10-09 22:28:03 UTC
Update date2017-01-19 02:36:12 UTC
FoodComEx IDPC000081
FoodDB RecordFDB000570
Chemical Information
DescriptionProline or L-proline abbreviated Pro or is one of the twenty amino acids used in living organisms as the building blocks of proteins. Proline is sometimes called an imino acid, although the IUPAC definition of an imine requires a carbon-nitrogen double bond. Proline is a non-essential amino acid that is largely synthesized from glutamic acid. While proline biosynthetic pathways exist from eubacteria to eukaryotes, in the most prevalent pathway, proline is cyclized from glutamate. First glutamate is phosphorylated to gamma-glutamyl phosphate by gamma-glutamyl kinase, then second, reduced to gamma-glutamyl semialdehyde by gamma-glutamyl phosphate reductase, then third, cyclized spontaneously to delta(1)-pyrroline-5-carboxylate and fourth, reduced to proline by delta(1)-pyrroline-5-carboxylate reductase. In higher plants and animals, the first two steps are catalysed by a bi-functional delta(1) -pyrroline-5-carboxylate synthase. Alternative pathways of proline formation use the initial steps of the arginine biosynthetic pathway to ornithine, which can be converted to delta(1)-pyrroline-5-carboxylate by ornithine aminotransferase and then reduced to proline or converted directly to proline by ornithine cyclodeaminase (PMID: 25367752). Proline is an essential component of collagen and is important for proper functioning of joints and tendons. It is a potential endogenous excitotoxin/neurotoxin, which causes damage to nerve cells and nerve tissues. Proline, when injected into the brains of rats, non-selectively destroyed pyramidal and granule cells (PMID: 3409032) suggesting that it can act as a neurotoxin. Proline can also be a metabotoxin which is an endogenously produced metabolite that causes adverse health effects at chronically high levels. At least five inborn errors of metabolism, including hyperprolinemia type I, hyperprolinemia type II, iminoglycinuria, prolinemia type II, and pyruvate carboxylase deficiency are associated with chronically high levels of proline (PMID: 18806117). Hyperprolinemia I and II are caused by deficiencies in the enzymatic activities of proline dehydrogenase and Delta-1-pyrroline-5-carboxylate reductase, respectively.
CAS Number147-85-3
(-)-2-Pyrrolidinecarboxylic acidbiospider
(2S)-Pyrrolidine-2-carboxylic acidbiospider
(S)-(-)-Pyrrolidine-2-carboxylic acidbiospider
(S)-2-Pyrralidinecarboxylic acidbiospider
(S)-2-Pyrrolidinecarboxylic acidbiospider
(S)-Pyrrolidine-2-carboxylic acidbiospider
2-Pyrralidinecarboxylic acid, (S)-biospider
2-Pyrrolidinecarboxylic acidChEBI
2-Pyrrolidinecarboxylic acid, (S)-biospider
FEMA 3319db_source
L-a-Pyrrolidinecarboxylic acidGenerator
L-alpha-Pyrrolidinecarboxylic acidbiospider
L-Pyrrolidine-2-carboxylic acidChEBI
L-α-pyrrolidinecarboxylic acidGenerator
Proline, 9CI; L-formdb_source
Chemical FormulaC5H9NO2
IUPAC name(2S)-pyrrolidine-2-carboxylic acid
InChI IdentifierInChI=1S/C5H9NO2/c7-5(8)4-2-1-3-6-4/h4,6H,1-3H2,(H,7,8)/t4-/m0/s1
Isomeric SMILESOC(=O)[C@@H]1CCCN1
Average Molecular Weight115.1305
Monoisotopic Molecular Weight115.063328537
Chemical Taxonomy
Description Belongs to the class of organic compounds known as proline and derivatives. Proline and derivatives are compounds containing proline or a derivative thereof resulting from reaction of proline at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentProline and derivatives
Alternative Parents
  • Proline or derivatives
  • Alpha-amino acid
  • L-alpha-amino acid
  • Pyrrolidine carboxylic acid
  • Pyrrolidine carboxylic acid or derivatives
  • Pyrrolidine
  • Amino acid
  • Carboxylic acid
  • Secondary aliphatic amine
  • Monocarboxylic acid or derivatives
  • Secondary amine
  • Organoheterocyclic compound
  • Azacycle
  • Organic oxygen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Amine
  • Organopnictogen compound
  • Organic oxide
  • Carbonyl group
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Aliphatic heteromonocyclic compound
Molecular FrameworkAliphatic heteromonocyclic compounds
External Descriptors
Physico-Chemical Properties - Experimental
Experimental logP-2.54HANSCH,C ET AL. (1995)
Experimental Water Solubility162 mg/mL at 25 oCMERCK INDEX (1996)
Melting PointMp 220-222° dec.DFC
Foods of Origin
FoodContent Range AverageReference
Production Data
Production Methodcommercial
Production Method ReferenceNot Available
Production Method Reference FileNot Available
Quantity AvailableProduction upon request, up to 1 g
Delivery TimeNot Available
Storage Formsolid
Storage Conditions-80°C
StabilityNot Available
PurityNot Available
Spectral Data Upon RequestNot Available
Provider Information
Contact NameContact InstitutionContact Email
Rosa Vazquez
Commercial Vendors
AKSci A131
AKSci J90475
Glentham GM1129
Glentham GM9897
MetaSci HMDB0000162
Sigma-Aldrich HMDB0000162
Toronto Research Chemicals P755995