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Record Information
StatusExpected but not Quantified
Creation Date2009-11-30 15:51:36 UTC
Update Date2020-02-26 21:38:24 UTC
Secondary Accession Numbers
  • HMDB13244
Metabolite Identification
Common NameLipid A
DescriptionLipid A is a lipid component of an endotoxin held responsible for toxicity of Gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide (LPS, also called endotoxin) molecule, and its hydrophobic nature allows it to anchor the LPS to the outer membrane. While its toxic effects can be damaging, the sensing of lipid A by the human immune system may also be critical for the onset of immune responses to Gram-negative infection, and for the subsequent successful fight against the infection. Many of the immune activating abilities of LPS can be attributed to the lipid A unit. It is a very potent stimulant of the immune system, activating cells (for example, monocytes or macrophages) at picogram per milliliter quantities. Lipid A has been found in Escherichia, Pseudomonas, Salmonella and meningococcus (PMID: 11948150 ; PMID: 12045108 ).
E. coli lipid aChEBI
Diphosphoryl hexaacyl lipid aHMDB
Synthetic e. coli lipid aHMDB
a, LipidHMDB
Lipid aMeSH
Chemical FormulaC94H178N2O25P2
Average Molecular Weight1798.365
Monoisotopic Molecular Weight1797.21939228
IUPAC Name{[(2R,3S,4R,5R,6R)-5-[(3R)-3-(dodecanoyloxy)tetradecanamido]-6-{[(2R,3S,4R,5R,6R)-3-hydroxy-5-[(3R)-3-hydroxytetradecanamido]-4-{[(3R)-3-hydroxytetradecanoyl]oxy}-6-(phosphonooxy)oxan-2-yl]methoxy}-2-(hydroxymethyl)-4-{[(3R)-3-(tetradecanoyloxy)tetradecanoyl]oxy}oxan-3-yl]oxy}phosphonic acid
Traditional Namelipid A
CAS Registry NumberNot Available
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as acylaminosugars. These are organic compounds containing a sugar linked to a chain through N-acyl group.
KingdomOrganic compounds
Super ClassOrganic oxygen compounds
ClassOrganooxygen compounds
Sub ClassCarbohydrates and carbohydrate conjugates
Direct ParentAcylaminosugars
Alternative Parents
  • Acylaminosugar
  • Saccharolipid
  • Hexose phosphate
  • Disaccharide phosphate
  • N-acyl-alpha-hexosamine
  • Tetracarboxylic acid or derivatives
  • Disaccharide
  • Glycosyl compound
  • O-glycosyl compound
  • Monoalkyl phosphate
  • Beta-hydroxy acid
  • Fatty acid ester
  • Alkyl phosphate
  • Fatty acyl
  • Phosphoric acid ester
  • Oxane
  • Organic phosphoric acid derivative
  • N-acyl-amine
  • Hydroxy acid
  • Fatty amide
  • Secondary carboxylic acid amide
  • Secondary alcohol
  • Carboxamide group
  • Carboxylic acid ester
  • Oxacycle
  • Organoheterocyclic compound
  • Carboxylic acid derivative
  • Acetal
  • Hydrocarbon derivative
  • Primary alcohol
  • Alcohol
  • Carbonyl group
  • Organonitrogen compound
  • Organopnictogen compound
  • Organic oxide
  • Organic nitrogen compound
  • Aliphatic heteromonocyclic compound
Molecular FrameworkAliphatic heteromonocyclic compounds
External Descriptors


Biological location:

Physical Properties
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility0.0012 g/LALOGPS
pKa (Strongest Acidic)0.61ChemAxon
pKa (Strongest Basic)-3ChemAxon
Physiological Charge-4ChemAxon
Hydrogen Acceptor Count19ChemAxon
Hydrogen Donor Count10ChemAxon
Polar Surface Area405.53 ŲChemAxon
Rotatable Bond Count88ChemAxon
Refractivity477.18 m³·mol⁻¹ChemAxon
Polarizability213.02 ųChemAxon
Number of Rings2ChemAxon
Rule of FiveNoChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0089-0123161900-a0b29cb2a5620669c282Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0ff1-1223093400-c7c1cee9a9256bd28b6eSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-00e9-0242489600-77966b68d48be8286cb4Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-002b-9510133200-a35ef4a869747eee82f3Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-004i-9010121101-806a5bc007a2af4acfaeSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-004i-9000000000-0c15069faff9658a6001Spectrum
Biological Properties
Cellular Locations
  • Membrane (predicted from logP)
Biospecimen LocationsNot Available
Tissue LocationsNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FooDB IDFDB029354
KNApSAcK IDNot Available
Chemspider ID8052983
KEGG Compound IDC13908
BioCyc IDCPD0-1283
BiGG IDNot Available
Wikipedia LinkLipid A
METLIN IDNot Available
PubChem Compound9877306
PDB IDNot Available
ChEBI ID134256
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB ID
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. Tzeng YL, Datta A, Kolli VK, Carlson RW, Stephens DS: Endotoxin of Neisseria meningitidis composed only of intact lipid A: inactivation of the meningococcal 3-deoxy-D-manno-octulosonic acid transferase. J Bacteriol. 2002 May;184(9):2379-88. [PubMed:11948150 ]
  2. Raetz CR, Whitfield C: Lipopolysaccharide endotoxins. Annu Rev Biochem. 2002;71:635-700. doi: 10.1146/annurev.biochem.71.110601.135414. Epub 2001 Nov 9. [PubMed:12045108 ]