Record Information
Version 1.0
Update Date 1/22/2018 12:54:54 PM
Metabolite IDPAMDB000198
Name: Citrulline
Description:Citrulline is an amino acid 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 (NOS; EC In this reaction arginine is first oxidized into N-hydroxyl-arginine, which is then further oxidized to citrulline concomitant with the release of nitric oxide.; EC Citrulline's name is derived from citrullus, the Latin word for watermelon, from which it was first isolated.
  • α-amino-γ-ureidovalerate
  • α-amino-γ-ureidovaleric acid
  • γureidonorvaline
  • (2S)-2-amino-5-(carbamoylamino)pentanoate
  • (2S)-2-amino-5-(carbamoylamino)pentanoic acid
  • (S)-2-amino-5-(aminocarbonyl)aminopentanoate
  • (S)-2-amino-5-(aminocarbonyl)aminopentanoic acid
  • (S)-2-Amino-5-ureidopentanoate
  • (S)-2-Amino-5-ureidopentanoic acid
  • 2-Amino-5-uredovalerate
  • 2-Amino-5-uredovaleric acid
  • 2-Amino-5-ureidovalerate
  • 2-Amino-5-ureidovaleric acid
  • A-Amino-D-ureidovalerate
  • A-Amino-D-ureidovaleric acid
  • a-amino-delta-Ureidovalerate
  • a-amino-delta-Ureidovaleric acid
  • a-amino-g-Ureidovalerate
  • a-amino-g-Ureidovaleric acid
  • a-amino-δ-Ureidovalerate
  • a-amino-δ-Ureidovaleric acid
  • Alpha-Amino-delta-ureidovalerate
  • Alpha-Amino-delta-ureidovaleric acid
  • Alpha-Amino-gamma-ureidovalerate
  • Alpha-Amino-gamma-ureidovaleric acid
  • Amino-ureidovalerate
  • Amino-ureidovaleric acid
  • CIR
  • CIT
  • Citrulline
  • Cytrulline
  • D-Ureidonorvaline
  • Delta-Ureidonorvaline
  • DL-citrulline
  • Gammaureidonorvaline
  • H-Cit-oh
  • L(+)-2-Amino-5-ureidovalerate
  • L(+)-2-Amino-5-ureidovaleric acid
  • L(+)-Citrulline
  • L-2-Amino-5-ureido-valerate
  • L-2-Amino-5-ureido-valeric acid
  • L-2-Amino-5-ureidovalerate
  • L-2-Amino-5-ureidovaleric acid
  • L-Citrulline
  • L-Cytrulline
  • L-N5-carbamoyl-Ornithine
  • Nγ-carbamylornithine
  • N()-Carbamylornithine
  • N(5)-(Aminocarbonyl)-DL-Ornithine
  • N(delta)-Carbamylornithine
  • N(δ)-Carbamylornithine
  • N-Carbamylornithine
  • N5-(Aminocarbonyl)-L-ornithine
  • N5-(aminocarbonyl)-Ornithine
  • N5-(Aminocarbonyl)ornithine
  • N5-Carbamoyl-L-ornithine
  • N5-carbamoylornithine
  • N5-carbamylornithine
  • Nγ-carbamylornithine
  • N5-(Aminocarbonyl)-L-ornithine
  • N5-(aminocarbonyl)ornithine
  • ND-carbamylornithine
  • Ndelta-carbamy-ornithine
  • Ndelta-carbamylornithine
  • Ngamma-carbamylornithine
  • Sitrulline
  • Ureidonorvaline
  • Ureidovalerate
  • Ureidovaleric acid
  • α-amino-γ-Ureidovalerate
  • α-amino-γ-Ureidovaleric acid
  • α-amino-δ-Ureidovalerate
  • α-amino-δ-Ureidovaleric acid
  • δ-Ureidonorvaline
Chemical Formula: C6H13N3O3
Average Molecular Weight: 175.1857
Monoisotopic Molecular Weight: 175.095691297
CAS number: 372-75-8
IUPAC Name:(2S)-2-amino-5-(carbamoylamino)pentanoic acid
Traditional IUPAC Name: L-citrulline
Chemical Taxonomy
Taxonomy DescriptionThis compound belongs to the class of organic compounds known as d-alpha-amino acids. These are alpha amino acids which have the D-configuration of the alpha-carbon atom.
Kingdom Organic compounds
Super ClassOrganic acids and derivatives
Class Carboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct Parent D-alpha-amino acids
Alternative Parents
  • D-alpha-amino acid
  • Amino fatty acid
  • Fatty acyl
  • Fatty acid
  • Isourea
  • Carboximidamide
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboximidic acid derivative
  • Hydrocarbon derivative
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Primary aliphatic amine
  • Imine
  • Carbonyl group
  • Amine
  • Aliphatic acyclic compound
Molecular Framework Aliphatic acyclic compounds
External Descriptors
Physical Properties
State: Solid
Melting point: 235.5 °C
Experimental Properties:
Water Solubility:212 mg/mL [HMP experimental]PhysProp
LogP:-3.19 [SANGSTER (1994)]PhysProp
Predicted Properties
Water Solubility21.8 mg/mLALOGPS
pKa (Strongest Acidic)2.27ChemAxon
pKa (Strongest Basic)9.23ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count4ChemAxon
Polar Surface Area118.44 Å2ChemAxon
Rotatable Bond Count5ChemAxon
Refractivity41.33 m3·mol-1ChemAxon
Polarizability17.35 Å3ChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular Locations: Cytoplasm
Spectrum TypeDescriptionSplash Key
GC-MSGC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies)splash10-0a4i-0920000000-2d92b63cd5d9648023b8View in MoNA
GC-MSGC-MS Spectrum - GC-MS (3 TMS)splash10-00di-9610000000-2e7cd23afc2adcef35a3View in MoNA
GC-MSGC-MS Spectrum - GC-MSNot Available
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-0a4i-0900000000-4c1d7af748a47e489949View in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-00di-9000000000-988fced362fc0da157c9View in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-00di-9000000000-0818e0e8bcee12692498View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-004j-0900000000-5fa8a338dcd2f2a6bdd2View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-004i-0900000000-16763200aa07f7629ad4View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-03di-3900000000-d9cfc5187aa799f6f978View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-0a4i-0900000000-10ee9a593e13550bec1cView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-004i-0900000000-45d272576af34c9512a3View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-014i-3900000000-6177a284fdea5a3f1306View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-0a4i-0900000000-d9456d45e2dbd7a3df10View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positivesplash10-004i-0900000000-ada57cdc73bda93be483View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negativesplash10-008a-0904000000-23fbe48f82e515087d68View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negativesplash10-03di-5900000000-78afcbaf8b8b3eabf174View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negativesplash10-001i-0900000000-8fb191d4c20fd54b9282View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negativesplash10-00di-0900000000-da484f0362a8dca5127eView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Negativesplash10-00e9-0900000000-46229b4f77feabb3f857View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Negativesplash10-001i-0900000000-4aca1022c393602a297dView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Negativesplash10-001i-0900000000-3bc2eff2e907b7734cc8View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Negativesplash10-001i-3900000000-2613bf40e3be814da86fView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Negativesplash10-0006-9300000000-e83287bbc060eb9cf6f3View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Positivesplash10-056r-0900000000-694a8872bdfd7eec1f2bView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Positivesplash10-08fr-2900000000-15b4711991ea9985fb2bView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Positivesplash10-00di-9300000000-915fbb73e0b728420e4aView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Positivesplash10-00di-9000000000-67e60567f5c062728350View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Positivesplash10-00di-9000000000-25140713431edd7c5eeaView in MoNA
1D NMR13C NMR SpectrumNot Available
1D NMR1H NMR SpectrumNot Available
1D NMR1H NMR SpectrumNot Available
2D NMR[1H,1H] 2D NMR SpectrumNot Available
2D NMR[1H,13C] 2D NMR SpectrumNot Available
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Synthesis Reference: Kakimoto, Toshio; Shibatani, Takeji; Nishimura, Noriyuki; Chibata, Ichiro. Enzymic production of L-citrulline by Pseudomonas putida. Applied Microbiology (1971), 22(6), 992-9.
Material Safety Data Sheet (MSDS) Download (PDF)
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Pubchem Compound ID9750
Kegg IDC00327
ChemSpider ID9367
Ligand ExpoCIR