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Record Information
Version3.6
Creation Date2006-05-22 14:17:39 UTC
Update Date2013-02-09 00:11:29 UTC
HMDB IDHMDB02168
Secondary Accession NumbersNone
Metabolite Identification
Common NameSuperoxide
DescriptionSuperoxide is the anionic form O2. It is important as the product of the one-electron reduction of dioxygen (oxygen gas), which occurs widely in nature. With one unpaired electron, the superoxide ion is a free radical. It is also paramagnetic. The biological toxicity of superoxide is due to its capacity to inactivate iron-sulfur cluster containing enzymes (which are critical in a wide variety of metabolic pathways), thereby liberating free iron in the cell, which can undergo fenton-chemistry and generate the highly reactive hydroxyl radical. In its HO2 form, superoxide can also initiate lipid peroxidation of polyunsaturated fatty acids. It also reacts with carbonyl compounds and halogenated carbons to create toxic peroxy radicals. As such, superoxide is a main cause of oxidative stress. Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to Methemoglobin. Because superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide scavenging enzyme, superoxide dismutase, or SOD. SOD is an extremely efficient enzyme; it catalyzes the neutralization of superoxide nearly as fast as the two can diffuse together spontaneously in solution. Genetic inactivation ("knockout") of SOD produces deleterious phenotypes in organisms ranging from bacteria to mice. The latter species dies around 21 days after birth if the mitochondrial variant of SOD (Mn-SOD) is inactivated, and suffers from multiple pathologies, including reduced lifespan, liver cancer, muscle atrophy, cataracts and female infertility when the cytoplasmic (Cu, Zn -SOD) variant is inactivated. With one unpaired electron, the superoxide ion is a free radical and therefore paramagnetic. In living organisms, superoxide dismutase protects the cell from the deleterious effects of superoxides.
Structure
Thumb
Synonyms
  1. Dioxidanidyl
  2. Dioxide(1-)
  3. Hyperoxid
  4. Superoxide
  5. Superoxide anion
  6. Superoxide radical
  7. Superoxide radical anion
Chemical FormulaO2
Average Molecular Weight31.9988
Monoisotopic Molecular Weight31.989829244
IUPAC Nameoxidanidyloxidanyl
Traditional IUPAC Namesuperoxide
CAS Registry Number11062-77-4
SMILES
[O][O-]
InChI Identifier
InChI=1S/HO2/c1-2/h1H/p-1
InChI KeyOUUQCZGPVNCOIJ-UHFFFAOYSA-M
Chemical Taxonomy
KingdomInorganic Compounds
Super ClassHomogeneous Non-metal Compounds
ClassNon-metal Oxoanionic Compounds
Sub ClassNon-metal Superoxides
Other Descriptors
  • diatomic oxygen(ChEBI)
  • inorganic radical anion(ChEBI)
  • reactive oxygen species(ChEBI)
Substituents
  • N/A
Direct ParentNon-metal Superoxides
Ontology
StatusExpected and Not Quantified
Origin
  • Endogenous
Biofunction
  • Osmolyte, enzyme cofactor, signalling
ApplicationNot Available
Cellular locations
  • Cytoplasm
  • Extracellular
  • Mitochondria
  • Nucleus
  • Peroxisome
Physical Properties
StateSolid
Experimental Properties
PropertyValueReference
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
PropertyValueSource
logP-0.36ChemAxon
pKa (strongest acidic)5.8ChemAxon
pKa (strongest basic)-6.8ChemAxon
physiological charge-1ChemAxon
hydrogen acceptor count2ChemAxon
hydrogen donor count0ChemAxon
polar surface area23.06ChemAxon
rotatable bond count0ChemAxon
refractivity2.89ChemAxon
polarizability1.67ChemAxon
Spectra
SpectraNot Available
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
  • Mitochondria
  • Nucleus
  • Peroxisome
Biofluid LocationsNot Available
Tissue LocationNot Available
Pathways
NameSMPDB LinkKEGG Link
Degradation of SuperoxidesSMP00468Not Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
DrugBank Metabolite IDNot Available
Phenol Explorer Compound IDNot Available
Phenol Explorer Metabolite IDNot Available
FoodDB IDFDB022880
KNApSAcK IDNot Available
Chemspider ID4514331
KEGG Compound IDC00704
BioCyc IDNot Available
BiGG ID35743
Wikipedia LinkSuperoxide
NuGOwiki LinkHMDB02168
Metagene LinkHMDB02168
METLIN IDNot Available
PubChem Compound5359597
PDB IDNot Available
ChEBI ID18421
References
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General ReferencesNot Available

Enzymes

General function:
Involved in catalase activity
Specific function:
Occurs in almost all aerobically respiring organisms and serves to protect cells from the toxic effects of hydrogen peroxide. Promotes growth of cells including T-cells, B-cells, myeloid leukemia cells, melanoma cells, mastocytoma cells and normal and transformed fibroblast cells.
Gene Name:
CAT
Uniprot ID:
P04040
Molecular weight:
59755.82
Reactions
3-Hydroxyanthranilic acid + Oxygen → Cinnavalininate + Superoxide + Hydrogen peroxide + Hydrogen Iondetails
General function:
Involved in superoxide dismutase activity
Specific function:
Destroys superoxide anion radicals which are normally produced within the cells and which are toxic to biological systems.
Gene Name:
SOD2
Uniprot ID:
P04179
Molecular weight:
24750.015
Reactions
Superoxide + Hydrogen Ion → Oxygen + Hydrogen peroxidedetails
General function:
Involved in metal ion binding
Specific function:
Destroys radicals which are normally produced within the cells and which are toxic to biological systems.
Gene Name:
SOD1
Uniprot ID:
P00441
Molecular weight:
15935.685
Reactions
Superoxide + Hydrogen Ion → Oxygen + Hydrogen peroxidedetails
General function:
Involved in metal ion binding
Specific function:
Protect the extracellular space from toxic effect of reactive oxygen intermediates by converting superoxide radicals into hydrogen peroxide and oxygen.
Gene Name:
SOD3
Uniprot ID:
P08294
Molecular weight:
25850.675
Reactions
Superoxide + Hydrogen Ion → Oxygen + Hydrogen peroxidedetails