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Record Information
Creation Date2006-08-16 13:52:05 UTC
Update Date2017-08-16 03:42:06 UTC
Secondary Accession Numbers
  • HMDB01362
Metabolite Identification
Common NameHydrogen
DescriptionHydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H2. With an atomic weight of 1.00794, hydrogen is the lightest element. Besides the common H1 isotope, hydrogen exists as the stable isotope Deuterium and the unstable, radioactive isotope Tritium. Hydrogen is the most abundant of the chemical elements, constituting roughly 75% of the universe's elemental mass. Hydrogen can form compounds with most elements and is present in water and most organic compounds. It plays a particularly important role in acid-base chemistry, in which many reactions involve the exchange of protons between soluble molecules. Oxidation of hydrogen, in the sense of removing its electron, formally gives H+, containing no electrons and a nucleus which is usually composed of one proton. That is why H+ is often called a proton. This species is central to discussion of acids. Under the Bronsted-Lowry theory, acids are proton donors, while bases are proton acceptors. A bare proton H+ cannot exist in solution because of its strong tendency to attach itself to atoms or molecules with electrons. However, the term 'proton' is used loosely to refer to positively charged or cationic hydrogen, denoted H+. H2 is a product of some types of anaerobic metabolism and is produced by several microorganisms, usually via reactions catalyzed by iron- or nickel-containing enzymes called hydrogenases. These enzymes catalyze the reversible redox reaction between H2 and its component two protons and two electrons. Creation of hydrogen gas occurs in the transfer of reducing equivalents produced during pyruvate fermentation to water.
e 949ChEBI
Molecular hydrogenChEBI
Hydrogen gasHMDB
Chemical FormulaH2
Average Molecular Weight2.0159
Monoisotopic Molecular Weight2.015650064
IUPAC NameNot Available
Traditional NameNot Available
CAS Registry Number1333-74-0
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of chemical entities known as other non-metal hydrides. These are inorganic compounds in which the heaviest atom bonded to a hydrogen atom is belongs to the class of 'other non-metals'.
KingdomChemical entities
Super ClassInorganic compounds
ClassHomogeneous non-metal compounds
Sub ClassOther non-metal organides
Direct ParentOther non-metal hydrides
Alternative ParentsNot Available
  • Other non-metal hydride
Molecular FrameworkNot Available
External Descriptors
StatusExpected but not Quantified
  • Endogenous
  • Microbial
  • Osmolyte, enzyme cofactor, signalling
ApplicationNot Available
Cellular locations
  • Cytoplasm
  • Extracellular
  • Mitochondria
  • Nucleus
  • Lysosome
  • Endoplasmic reticulum
  • Golgi apparatus
  • Peroxisome
Physical Properties
Experimental Properties
Melting Point-259.2 °CNot Available
Boiling PointNot AvailableNot Available
Water Solubility0.00162 mg/mL at 21 °CNot Available
LogPNot AvailableNot Available
Predicted Properties
Physiological Charge0ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area0 Å2ChemAxon
Rotatable Bond Count0ChemAxon
Refractivity0 m3·mol-1ChemAxon
Polarizability0.74 Å3ChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0udi-9000000000-0595c445077141efd7acView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0udi-9000000000-0595c445077141efd7acView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0udi-9000000000-0595c445077141efd7acView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0udi-9000000000-cbcf030cfea82ec88da3View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0udi-9000000000-cbcf030cfea82ec88da3View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0udi-9000000000-cbcf030cfea82ec88da3View in MoNA
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
  • Mitochondria
  • Nucleus
  • Lysosome
  • Endoplasmic reticulum
  • Golgi apparatus
  • Peroxisome
Biofluid LocationsNot Available
Tissue LocationNot Available
Acute Intermittent PorphyriaSMP00344Not Available
Carnitine SynthesisSMP00465Not Available
Catecholamine BiosynthesisSMP00012map00350
Clomipramine Metabolism PathwaySMP00639Not Available
Congenital Erythropoietic Porphyria (CEP) or Gunther DiseaseSMP00345Not Available
Degradation of SuperoxidesSMP00468Not Available
Ethanol DegradationSMP00449Not Available
Hereditary Coproporphyria (HCP)SMP00342Not Available
Homocysteine DegradationSMP00455Not Available
Leigh SyndromeSMP00196Not Available
Malonic AciduriaSMP00198Not Available
Malonyl-coa decarboxylase deficiencySMP00502Not Available
Methylmalonic Aciduria Due to Cobalamin-Related DisordersSMP00201Not Available
Mitochondrial Beta-Oxidation of Long Chain Saturated Fatty AcidsSMP00482Not Available
Mitochondrial Beta-Oxidation of Medium Chain Saturated Fatty AcidsSMP00481Not Available
Mitochondrial Beta-Oxidation of Short Chain Saturated Fatty AcidsSMP00480Not Available
Mitochondrial Electron Transport ChainSMP00355map00190
Omeprazole Metabolism PathwaySMP00613Not Available
Omeprazole PathwaySMP00226Not Available
Pantoprazole Metabolism PathwaySMP00615Not Available
Pantoprazole PathwaySMP00228Not Available
Plasmalogen SynthesisSMP00479Not Available
Porphyria Variegata (PV)SMP00346Not Available
Porphyrin MetabolismSMP00024map00860
Primary hyperoxaluria II, PH2SMP00558Not Available
Propanoate MetabolismSMP00016map00640
Pyruvaldehyde DegradationSMP00459Not Available
Pyruvate Decarboxylase E1 Component Deficiency (PDHE1 Deficiency)SMP00334Not Available
Pyruvate Dehydrogenase Complex DeficiencySMP00212Not Available
Pyruvate kinase deficiencySMP00559Not Available
Pyruvate MetabolismSMP00060map00620
Rabeprazole Metabolism PathwaySMP00616Not Available
Rabeprazole PathwaySMP00229Not Available
Threonine and 2-Oxobutanoate DegradationSMP00452Not Available
Transfer of Acetyl Groups into MitochondriaSMP00466Not Available
Trehalose DegradationSMP00467Not Available
Warburg EffectSMP00654Not 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 IDFDB016247
KNApSAcK IDNot Available
Chemspider ID762
KEGG Compound IDC00282
BiGG ID33778
Wikipedia LinkHydrogen
NuGOwiki LinkHMDB0001362
METLIN IDNot Available
PubChem Compound783
PDB IDNot Available
ChEBI ID18276
Synthesis ReferenceAit-Ichou, I.; Formenti, M.; Pommier, B.; Teichner, S. J. Photocatalytic dehydrogenation of isopropanol on platinum/titania catalysts. Journal of Catalysis (1985), 91(2), 293-307.
Material Safety Data Sheet (MSDS)Not Available
General ReferencesNot Available


General function:
Involved in ion channel activity
Specific function:
Mediates the voltage-dependent proton permeability of excitable membranes. Forms a proton-selective channel through which protons may pass in accordance with their electrochemical gradient. Proton efflux, accompanied by membrane depolarization, facilitates acute production of reactive oxygen species in phagocytosis
Gene Name:
Uniprot ID:
Molecular weight: