Citrulline (CHEM003255)

Record Information
Version1.0
Creation Date2014-08-29 06:16:39 UTC
Update Date2026-05-14 16:24:20 UTC
Accession NumberCHEM003255
Identification
Common NameCitrulline
ClassSmall Molecule
Description
Citrulline is an amino acid. It is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle. It is also produced from arginine as a by-product of the reaction catalyzed by NOS family. Its name is derived from citrullus, the Latin word for watermelon, from which it was first isolated.
Contaminant Sources
  • FooDB Chemicals
  • HMDB Contaminants - Urine
  • T3DB toxins
Contaminant Type
  • Amide
  • Amine
  • Animal Toxin
  • Dietary Supplement
  • Drug
  • Food Toxin
  • Metabolite
  • Micronutrient
  • Natural Compound
  • Non-Essential Amino Acid
  • Nutraceutical
  • Organic Compound
  • Supplement
Chemical Structure
MOLSDFPDBSMILESInChI
Synonyms
ValueSource
(S)-2-Amino-5-ureidopentanoic acidChEBI
2-Amino-5-ureidovaleric acidChEBI
alpha-Amino-delta-ureidovaleric acidChEBI
CitChEBI
delta-UreidonorvalineChEBI
L-2-Amino-5-ureidovaleric acidChEBI
N(5)-(Aminocarbonyl)-L-ornithineChEBI
N5-(Aminocarbonyl)ornithineChEBI
N5-CarbamoylornithineChEBI
N(delta)-CarbamylornithineChEBI
(S)-2-Amino-5-ureidopentanoateGenerator
2-Amino-5-ureidovalerateGenerator
a-Amino-delta-ureidovalerateGenerator
a-Amino-delta-ureidovaleric acidGenerator
alpha-Amino-delta-ureidovalerateGenerator
Α-amino-δ-ureidovalerateGenerator
Α-amino-δ-ureidovaleric acidGenerator
Δ-ureidonorvalineGenerator
L-2-Amino-5-ureidovalerateGenerator
N(Δ)-carbamylornithineGenerator
a-Amino-δ-ureidovalerateHMDB
a-Amino-δ-ureidovaleric acidHMDB
(2S)-2-Amino-5-(carbamoylamino)pentanoateHMDB
(2S)-2-Amino-5-(carbamoylamino)pentanoic acidHMDB
(S)-2-Amino-5-(aminocarbonyl)aminopentanoateHMDB
(S)-2-Amino-5-(aminocarbonyl)aminopentanoic acidHMDB
2-Amino-5-uredovalerateHMDB
2-Amino-5-uredovaleric acidHMDB
a-Amino-D-ureidovalerateHMDB
a-Amino-D-ureidovaleric acidHMDB
alpha-Amino-gamma-ureidovalerateHMDB
alpha-Amino-gamma-ureidovaleric acidHMDB
Amino-ureidovalerateHMDB
Amino-ureidovaleric acidHMDB
CIRHMDB
CytrullineHMDB
D-UreidonorvalineHMDB
DL-CitrullineHMDB
GammaureidonorvalineHMDB
H-Cit-OHHMDB
L(+)-2-Amino-5-ureidovalerateHMDB
L(+)-2-Amino-5-ureidovaleric acidHMDB
L(+)-CitrullineHMDB
L-2-Amino-5-ureido-valerateHMDB
L-2-Amino-5-ureido-valeric acidHMDB
L-CitrullineHMDB
L-CytrullineHMDB
L-N5-Carbamoyl-ornithineHMDB
N()-CarbamylornithineHMDB
N(5)-(Aminocarbonyl)-DL-ornithineHMDB
N-CarbamylornithineHMDB
N5-(Aminocarbonyl)-L-ornithineHMDB
N5-(Aminocarbonyl)-ornithineHMDB
N5-Carbamoyl-L-ornithineHMDB
N5-CarbamylornithineHMDB
ND-CarbamylornithineHMDB
Ndelta-carbamy-ornithineHMDB
Ndelta-carbamylornithineHMDB
Ngamma-carbamylornithineHMDB
SitrullineHMDB
UreidonorvalineHMDB
UreidovalerateHMDB
Ureidovaleric acidHMDB
Chemical FormulaC6H13N3O3
Average Molecular Mass175.186 g/mol
Monoisotopic Mass175.096 g/mol
CAS Registry Number372-75-8
IUPAC Name(2S)-2-amino-5-(carbamoylamino)pentanoic acid
Traditional NameL-citrulline
SMILESN[C@@H](CCCNC(N)=O)C(O)=O
InChI IdentifierInChI=1S/C6H13N3O3/c7-4(5(10)11)2-1-3-9-6(8)12/h4H,1-3,7H2,(H,10,11)(H3,8,9,12)/t4-/m0/s1
InChI KeyRHGKLRLOHDJJDR-BYPYZUCNSA-N
Chemical Taxonomy
Description Belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentL-alpha-amino acids
Alternative Parents
Substituents
  • L-alpha-amino acid
  • Fatty acid
  • Isourea
  • Amino acid
  • Carboximidic acid derivative
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Carboximidamide
  • Amine
  • Hydrocarbon derivative
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Organic oxide
  • Primary aliphatic amine
  • Organopnictogen compound
  • Imine
  • Organic oxygen compound
  • Organic nitrogen compound
  • Carbonyl group
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginEndogenous
Cellular Locations
  • Membrane
  • Mitochondria
Biofluid LocationsNot Available
Tissue Locations
  • Bladder
  • Epidermis
  • Fibroblasts
  • Intestine
  • Kidney
  • Liver
  • Myelin
  • Nerve Cells
  • Neuron
  • Placenta
  • Platelet
  • Prostate
Pathways
NameSMPDB LinkKEGG Link
Arginine and Proline MetabolismSMP00020 map00330
Aspartate MetabolismSMP00067 map00250
Urea CycleSMP00059 Not Available
Argininosuccinic AciduriaSMP00003 Not Available
Citrullinemia Type ISMP00001 Not Available
Pyruvate Carboxylase DeficiencySMP00350 Not Available
Saccharopinuria/Hyperlysinemia IISMP00239 Not Available
Applications
Biological Roles
Chemical Roles
Physical Properties
StateSolid
AppearanceWhite powder.
Experimental Properties
PropertyValue
Melting Point235.5°C
Boiling PointNot Available
Solubility200 g/L (at 20°C)
Predicted Properties
PropertyValueSource
Water Solubility21.8 g/LALOGPS
logP-3.3ALOGPS
logP-3.9ChemAxon
logS-0.9ALOGPS
pKa (Strongest Acidic)2.27ChemAxon
pKa (Strongest Basic)9.23ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count4ChemAxon
Polar Surface Area118.44 ŲChemAxon
Rotatable Bond Count5ChemAxon
Refractivity41.33 m³·mol⁻¹ChemAxon
Polarizability17.35 ųChemAxon
Number of Rings0ChemAxon
BioavailabilityYesChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectra
Spectra
Toxicity Profile
Route of ExposureNot Available
Mechanism of ToxicityL-citrulline is converted to L-arginine by argininosuccinate synthase. L-arginine is in turn responsible for citrulline's therapeutic affects. Many of L-arginine's activities, including its possible anti-atherogenic actions, may be accounted for by its role as the precursor to nitric oxide or NO. NO is produced by all tissues of the body and plays very important roles in the cardiovascular system, immune system and nervous system. NO is formed from L-arginine via the enzyme nitric oxide synthase or synthetase (NOS), and the effects of NO are mainly mediated by 3',5' -cyclic guanylate or cyclic GMP. NO activates the enzyme guanylate cyclase, which catalyzes the synthesis of cyclic GMP from guanosine triphosphate or GTP. Cyclic GMP is converted to guanylic acid via the enzyme cyclic GMP phosphodiesterase.

NOS is a heme-containing enzyme with some sequences similar to cytochrome P-450 reductase. Several isoforms of NOS exist, two of which are constitutive and one of which is inducible by immunological stimuli. The constitutive NOS found in the vascular endothelium is designated eNOS and that present in the brain, spinal cord and peripheral nervous system is designated nNOS. The form of NOS induced by immunological or inflammatory stimuli is known as iNOS. iNOS may be expressed constitutively in select tissues such as lung epithelium.

All the nitric oxide synthases use NADPH (reduced nicotinamide adenine dinucleotide phosphate) and oxygen (O2) as cosubstrates, as well as the cofactors FAD (flavin adenine dinucleotide), FMN (flavin mononucleotide), tetrahydrobiopterin and heme. Interestingly, ascorbic acid appears to enhance NOS activity by increasing intracellular tetrahydrobiopterin. eNOS and nNOS synthesize NO in response to an increased concentration of calcium ions or in some cases in response to calcium-independent stimuli, such as shear stress. In vitro studies of NOS indicate that the Km of the enzyme for L-arginine is in the micromolar range. The concentration of L-arginine in endothelial cells, as well as in other cells, and in plasma is in the millimolar range. What this means is that, under physiological conditions, NOS is saturated with its L-arginine substrate. In other words, L-arginine would not be expected to be rate-limiting for the enzyme, and it would not appear that supraphysiological levels of L-arginine which could occur with oral supplementation of the amino acid would make any difference with regard to NO production. The reaction would appear to have reached its maximum level. However, in vivo studies have demonstrated that, under certain conditions, e.g. hypercholesterolemia, L-arginine could enhance endothelial-dependent vasodilation and NO production.
MetabolismNot Available
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesUsed for nutritional supplementation, also for treating dietary shortage or imbalance.
Minimum Risk LevelNot Available
Health EffectsNot Available
SymptomsNot Available
TreatmentNot Available
Concentrations
Not Available
External Links
DrugBank IDDB00155
HMDB IDHMDB0000904
FooDB IDFDB011841
Phenol Explorer IDNot Available
KNApSAcK IDC00001348
BiGG ID34627
BioCyc IDL-CITRULLINE
METLIN ID16
PDB IDNot Available
Wikipedia LinkCitrulline
Chemspider ID9367
ChEBI ID16349
PubChem Compound ID9750
Kegg Compound IDC00327
YMDB IDYMDB00060
ECMDB IDECMDB00904
References
Synthesis Reference

Hua Bai, Peijie Yang, Zhengjie Chen, Chongyan Xu, Zhaorul Li, Zigang Zhao, Luyan Jiang, Zongyi Yang, Jiang Li, “PROCESSES FOR THE PRODUCTION OF L-CITRULLINE.” U.S. Patent US20090142813, issued June 04, 2009.

MSDSLink
General References
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7. Kakimoto, Toshio; Shibatani, Takeji; Nishimura, Noriyuki; Chibata, Ichiro. Enzymic production of L-citrulline by Pseudomonas putida. Applied Microbiology (1971), 22(6), 992-9.
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