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Record Information
StatusDetected and Quantified
Creation Date2005-11-16 15:48:42 UTC
Update Date2021-01-04 21:29:32 UTC
Secondary Accession Numbers
  • HMDB00670
Metabolite Identification
Common NameHomo-L-arginine
DescriptionL-homoarginine, also known as N6-(aminoiminomethyl)-L-lysine or N6-amidino-L-lysine, is a member of the class of compounds known as L-alpha-amino acids. L-alpha-amino acids are alpha amino acids which have the L-configuration of the alpha-carbon atom. More specifically, L-homoarginine is a naturally occurring, non-proteinogenic, cationic amino acid. It is formed in the liver in a reaction catalyzed by L-arginine:glycine amidinotransferase (AGAT) when transferring the amidino group from arginine to lysine. It is an alternative substrate for nitric oxide (NO) synthase. L-homoarginine increases the availability of NO and thereby affects endothelial function. High homoarginine levels may exert positive actions that are relevant to cardiovascular health, including enhanced endothelial function, inhibition of platelet aggregation and stimulation of insulin secretion (PMID: 30866658 ). Recent studies have demonstrated that low serum homoarginine levels are a strong predictor of cardiovascular mortality (PMID: 24583919 ). L-homoarginine is a substrate of the human cationic amino acid CAT1 [solute carrier family 7 (SLC7A1)], CAT2A (SLC7A2A) or CAT2B (SLC7A2B) (PMID: 28684763 ). According to published human metabolomic data, L-homoarginine can be found primarily in blood, cerebrospinal fluid (CSF), and urine, as well as in human intestinal and testes tissues. Moreover, L-homoarginine has been found to be associated with liver cirrhosis and the genetic disorder, hyperargininemia. Homoarginine is an organ-specific uncompetitive inhibitor of human liver and bone alkaline phosphohydrolase (PMID: 5063678 ).
Chemical FormulaC7H16N4O2
Average Molecular Weight188.2275
Monoisotopic Molecular Weight188.127325776
IUPAC Name(2S)-2-amino-6-carbamimidamidohexanoic acid
Traditional NameL-homoarginine
CAS Registry Number156-86-5
InChI Identifier
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
  • L-alpha-amino acid
  • Medium-chain fatty acid
  • Amino fatty acid
  • Fatty acid
  • Fatty acyl
  • Guanidine
  • Amino acid
  • Carboximidamide
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Organic oxide
  • Organopnictogen compound
  • Organic oxygen compound
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Primary aliphatic amine
  • Imine
  • Carbonyl group
  • Organic nitrogen compound
  • Amine
  • Hydrocarbon derivative
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Physiological effect

Health effect:


Route of exposure:


Biological location:


Industrial application:

Physical Properties
Experimental Properties
Melting Point213 - 215 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility1.58 g/LALOGPS
pKa (Strongest Acidic)2.49ChemAxon
pKa (Strongest Basic)12.3ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count6ChemAxon
Hydrogen Donor Count5ChemAxon
Polar Surface Area125.22 ŲChemAxon
Rotatable Bond Count6ChemAxon
Refractivity58.52 m³·mol⁻¹ChemAxon
Polarizability20.04 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-00dl-9200000000-4b838fa08e1357002dbfSpectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-006x-8900000000-fed7c106a20ecedc84aeSpectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-000i-1900000000-be624ee9b24e82eb0742Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-001i-9100000000-f4d4f5ac890116d181f0Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-053r-9000000000-4414ba2f5a6f7d2b30ccSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Negativesplash10-000i-0900000000-46385e830fe015de53abSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Negativesplash10-0002-0900000000-c6d6b6435e521a93b453Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Negativesplash10-0002-0900000000-6e5c16a8db2bbd58844fSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Negativesplash10-0002-6900000000-a844ac9257f1ef5a3b23Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Negativesplash10-0006-9000000000-f496e2b96544aa9df21dSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Positivesplash10-000i-0900000000-860f0c1c052c981b2f3bSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Positivesplash10-001c-1900000000-6ea950560557eb3afd98Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Positivesplash10-001i-9300000000-d110eb7150669bcdc29cSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Positivesplash10-001i-9000000000-2f0ed2e02fdc77532125Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Positivesplash10-001i-9000000000-d1b2d06e85c976b4efa5Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-000i-0900000000-46385e830fe015de53abSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0002-0900000000-c6d6b6435e521a93b453Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0002-0900000000-e278e373c633748b7f2aSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0002-6900000000-2a53a55ea05925b3a0e7Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0006-9000000000-f496e2b96544aa9df21dSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-000i-0900000000-860f0c1c052c981b2f3bSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-000f-1900000000-78f1894c2529837e5d1aSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-01qc-7900000000-c7e53e1427434aef74afSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-03di-9000000000-1920df59a18f799043abSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-000j-1900000000-c97e2b766559765479ddSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-052b-5900000000-16bff7159fd55d679369Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0006-9000000000-abe2fe3203bf8dcb8f8fSpectrum
1D NMR13C NMR SpectrumNot AvailableSpectrum
1D NMR1H NMR SpectrumNot AvailableSpectrum
2D NMR[1H,13C] 2D NMR SpectrumNot AvailableSpectrum
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biospecimen Locations
  • Blood
  • Cerebrospinal Fluid (CSF)
  • Feces
  • Urine
Tissue Locations
  • Intestine
  • Placenta
  • Testis
Normal Concentrations
BloodDetected and Quantified2.00 +/- 0.60 uMAdult (>18 years old)MaleNormal details
BloodDetected and Quantified6.0 (0.52-12.3) uMAdult (>18 years old)BothNormal details
BloodDetected and Quantified1.12 +/- 0.60 uMAdult (>18 years old)BothNormal details
Cerebrospinal Fluid (CSF)Detected and Quantified0.7 +/- 0.4 uMAdult (>18 years old)MaleNormal details
Cerebrospinal Fluid (CSF)Detected and Quantified0.7 +/- 0.2 uMAdult (>18 years old)FemaleNormal details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
UrineDetected and Quantified0.04342 +/- 0.01184 umol/mmol creatinineAdult (>18 years old)Not SpecifiedNormal details
UrineDetected and Quantified0.98 (0.0-1.98) umol/mmol creatinineAdult (>18 years old)BothNormal details
Abnormal Concentrations
BloodDetected and Quantified1.65 +/- 0.70 uMAdult (>18 years old)BothCirrhosis details
Cerebrospinal Fluid (CSF)Detected and Quantified1.16 uMAdult (>18 years old)BothHyperargininemia details
Associated Disorders and Diseases
Disease References
  1. Marescau B, De Deyn PP, Holvoet J, Possemiers I, Nagels G, Saxena V, Mahler C: Guanidino compounds in serum and urine of cirrhotic patients. Metabolism. 1995 May;44(5):584-8. [PubMed:7752905 ]
  1. Mizutani N, Hayakawa C, Ohya Y, Watanabe K, Watanabe Y, Mori A: Guanidino compounds in hyperargininemia. Tohoku J Exp Med. 1987 Nov;153(3):197-205. [PubMed:3433275 ]
Associated OMIM IDs
DrugBank IDDB03974
Phenol Explorer Compound IDNot Available
FooDB IDFDB001490
KNApSAcK IDC00001364
Chemspider ID8732
KEGG Compound IDC01924
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkNot Available
PubChem Compound9085
PDB IDNot Available
ChEBI ID27747
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB IDMDB00000212
Synthesis ReferenceIzumiya, Nobuo. Synthesis of DL-homoarginine and Na-methyl-DL-homoarginine. Nippon Kagaku Zasshi (1951), 72 521-3. CODEN: NPKZAZ ISSN:0369-5387. CAN 46:42183 AN 1952:42183
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Mori A, Watanabe Y, Fujimoto N: Fluorometrical analysis of guanidino compounds in human cerebrospinal fluid. J Neurochem. 1982 Feb;38(2):448-50. [PubMed:7108550 ]
  2. Tamura Y, Fujii S: Purification of human plasma kallikrein and urokinase by affinity chromatography. J Biochem. 1976 Sep;80(3):507-11. [PubMed:824284 ]
  3. Shoda J, Tanaka N, Osuga T, Matsuura K, Miyazaki H: Altered bile acid metabolism in liver disease: concurrent occurrence of C-1 and C-6 hydroxylated bile acid metabolites and their preferential excretion into urine. J Lipid Res. 1990 Feb;31(2):249-59. [PubMed:2324645 ]
  4. Lin CW, Fishman WH: L-Homoarginine. An organ-specific, uncompetitive inhibitor of human liver and bone alkaline phosphohydrolases. J Biol Chem. 1972 May 25;247(10):3082-7. [PubMed:5063678 ]
  5. Marescau B, Qureshi IA, De Deyn P, Letarte J, Ryba R, Lowenthal A: Guanidino compounds in plasma, urine and cerebrospinal fluid of hyperargininemic patients during therapy. Clin Chim Acta. 1985 Feb 28;146(1):21-7. [PubMed:3987036 ]
  6. Brock DJ: Amniotic fluid alkaline phosphatase isoenzymes in early prenatal diagnosis of cystic fibrosis. Lancet. 1983 Oct 22;2(8356):941-3. [PubMed:6138505 ]
  7. Crofton PM, Smith AF: Alkaline phosphatase of high and low molecular mass in human serum and bile: a comparative study of kinetic properties. Clin Chem. 1980 Mar;26(3):451-6. [PubMed:7363466 ]
  8. el-Mokhefi Z, Duvivier J, Plomteux G, Gielen J: [Biochemical characterization of a high-molecular weight alkaline phosphatase in a patient with cholangiocarcinoma (alpha-1 alkaline phosphatase)]. Ann Biol Clin (Paris). 1985;43(3):215-20. [PubMed:2411171 ]
  9. Muller F, Berg S, Frot JC, Boue J, Boue A: Prenatal diagnosis of cystic fibrosis. I. Prospective study of 51 pregnancies. Prenat Diagn. 1985 Mar-Apr;5(2):97-108. [PubMed:2581242 ]
  10. Chang CH, Angellis D, Fishman WH: Presence of the rare D-variant heat-stable, placental-type alkaline phosphatase in normal human testis. Cancer Res. 1980 May;40(5):1506-10. [PubMed:6154531 ]
  11. Mizutani N, Hayakawa C, Ohya Y, Watanabe K, Watanabe Y, Mori A: Guanidino compounds in hyperargininemia. Tohoku J Exp Med. 1987 Nov;153(3):197-205. [PubMed:3433275 ]
  12. Gatti R, Gioia MG: Anisoin: a useful pre-chromatographic derivatization fluorogenic reagent for LC analysis of guanidino compounds. J Pharm Biomed Anal. 2006 Sep 11;42(1):11-6. Epub 2006 Feb 3. [PubMed:16460903 ]
  13. Marescau B, De Deyn PP, Lowenthal A, Qureshi IA, Antonozzi I, Bachmann C, Cederbaum SD, Cerone R, Chamoles N, Colombo JP, et al.: Guanidino compound analysis as a complementary diagnostic parameter for hyperargininemia: follow-up of guanidino compound levels during therapy. Pediatr Res. 1990 Mar;27(3):297-303. [PubMed:1690873 ]
  14. Suzuki K, Yoshimura Y, Hisada Y, Matsumoto A: Sensitivity of intestinal alkaline phosphatase to L-homoarginine and its regulation by subunit-subunit interaction. Jpn J Pharmacol. 1994 Feb;64(2):97-102. [PubMed:7518015 ]
  15. Elshenawy S, Pinney SE, Stuart T, Doulias PT, Zura G, Parry S, Elovitz MA, Bennett MJ, Bansal A, Strauss JF 3rd, Ischiropoulos H, Simmons RA: The Metabolomic Signature of the Placenta in Spontaneous Preterm Birth. Int J Mol Sci. 2020 Feb 4;21(3). pii: ijms21031043. doi: 10.3390/ijms21031043. [PubMed:32033212 ]
  16. Karetnikova ES, Jarzebska N, Markov AG, Weiss N, Lentz SR, Rodionov RN: Is Homoarginine a Protective Cardiovascular Risk Factor? Arterioscler Thromb Vasc Biol. 2019 May;39(5):869-875. doi: 10.1161/ATVBAHA.118.312218. [PubMed:30866658 ]
  17. Sobczak A, Prokopowicz A, Radek M, Szula M, Zaciera M, Kurek J, Goniewicz ML: Tobacco smoking decreases plasma concentration of the emerging cardiovascular risk marker, L-homoarginine. Circ J. 2014;78(5):1254-8. doi: 10.1253/circj.cj-13-1334. Epub 2014 Feb 28. [PubMed:24583919 ]
  18. Chafai A, Fromm MF, Konig J, Maas R: The prognostic biomarker L-homoarginine is a substrate of the cationic amino acid transporters CAT1, CAT2A and CAT2B. Sci Rep. 2017 Jul 6;7(1):4767. doi: 10.1038/s41598-017-04965-2. [PubMed:28684763 ]


General function:
Involved in oxidoreductase activity
Specific function:
Produces nitric oxide (NO) which is implicated in vascular smooth muscle relaxation through a cGMP-mediated signal transduction pathway. NO mediates vascular endothelial growth factor (VEGF)-induced angiogenesis in coronary vessels and promotes blood clotting through the activation of platelets. Isoform eNOS13C: Lacks eNOS activity, dominant-negative form that may down-regulate eNOS activity by forming heterodimers with isoform 1.
Gene Name:
Uniprot ID:
Molecular weight:
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