Atlas of Human Biochemistry

The map of your metabolism

The central chemistry of a human cell on one chart. Point at a pathway to name it; select it to open its chapter.

Central pathways of human metabolismABCDEFGHIJKL12345678CytosolMitochondrionEndoplasmic reticulumHexokinase, glucokinaseHKPhosphoglucose isomerasePhosphofructokinase-1PFK-1Aldolase ATriose phosphate isomeraseGAPDH, phosphoglycerate kinase (NADH, ATP)Phosphoglycerate mutase, enolasePyruvate kinase (ATP)PKLactate dehydrogenaseLDHGlycolysisGlucose-6-phosphataseG6PaseFructose-1,6-bisphosphataseFBPasePyruvate carboxylase and PEP carboxykinase, via oxaloacetatePC, PEPCKGluconeogenesisVia glucose-1-phosphate: glycogen phosphorylase for breakdown, glycogen synthase via UDP-glucose for synthesisGlucose-6-phosphate dehydrogenase and two further steps (2 NADPH)G6PDRibose-5-phosphate isomerasePRPP synthetase and several stepsPentose phosphate pathwayKetohexokinase (fructokinase)KHKAldolase B; glyceraldehyde enters as glyceraldehyde-3-P via triokinaseAldolase BPyruvate dehydrogenase complex (thiamine pyrophosphate)PDHCitrate synthase, with oxaloacetateAconitaseIsocitrate dehydrogenase (NADH, CO₂)α-Ketoglutarate dehydrogenase (NADH, CO₂)Succinyl-CoA synthetase (GTP or ATP)Succinate dehydrogenase, complex II (FADH₂)FumaraseMalate dehydrogenase (NADH)Citrate synthaseCitric acid cycleNADH dehydrogenase (complex I) reduces ubiquinone; succinate dehydrogenase (complex II) also reduces ubiquinoneMetforminUbiquinol to cytochrome bc1 complex (complex III)Complex III reduces cytochrome cCytochrome c oxidase (complex IV) reduces O₂ to H₂OComplexes I, III and IV pump protons; the proton gradient drives ATP synthaseOxidative phosphorylationCarnitine palmitoyltransferase 1 and 2 (carnitine shuttle)CPT1Beta-oxidation spiral (FADH₂, NADH)Beta-oxidationCitrate export and ATP-citrate lyaseACLYAcetyl-CoA carboxylase 1 (ATP, biotin)ACCFatty acid synthase (NADPH)FASNAcyl-CoA synthetase, acyltransferases, with glycerol-3-PFatty acid synthesisGlycerol kinase (liver)Glycerol-3-phosphate dehydrogenaseThiolase, HMG-CoA synthase 2, HMG-CoA lyase (liver)HMGCS2KetogenesisAcetyl-CoA acetyltransferase 2HMG-CoA synthase 1HMG-CoA reductase (2 NADPH), rate-limitingHMGCRStatinsMevalonate kinase, phosphomevalonate kinase, mevalonate diphosphate decarboxylase (3 ATP)Isopentenyl-PP isomerase, farnesyl-PP synthaseFDPSPolyprenyl synthesis toward coenzyme Q10cis-PrenyltransferaseFarnesyltransferase, geranylgeranyl transferasesSqualene synthase (NADPH)FDFT1Squalene epoxidase, lanosterol synthaseSQLESeveral steps (Kandutsch-Russell branch; the Bloch branch ends with desmosterol and DHCR24)7-Dehydrocholesterol reductaseDHCR7Cholesterol 7α-hydroxylase and further steps (liver)CYP7A1Cholesterol side-chain cleavage enzyme in mitochondria of adrenal and gonadal cellsCYP11A1UVB photolysis in skin, then thermal isomerisationUVBCholesterol synthesisCarbamoyl phosphate synthetase 1 (2 ATP, activated by N-acetylglutamate)CPS1Ornithine transcarbamylase, with ornithineOTCArgininosuccinate synthetase, with aspartate (ATP)ASS1Argininosuccinate lyase, releases fumarateASLArginase 1ARG1Arginase 1 regenerates ornithineOrnithine import (ORNT1) to ornithine transcarbamylaseUrea cycleTransamination (aminotransferases, pyridoxal phosphate); glutamate dehydrogenaseAlanine aminotransferaseALTPHGDH, PSAT1, PSPH (three steps)Amino acidsDihydrofolate reductase, two reductions (NADPH)DHFRSerine hydroxymethyltransferase: serine to glycineSHMTMethylenetetrahydrofolate reductaseMTHFRMethionine synthase (vitamin B12) transfers the methyl group to homocysteineMethionine synthase (vitamin B12)MTR, B12Methionine adenosyltransferase (ATP)MATMethyltransferases donate the methyl groupS-adenosylhomocysteine hydrolaseAHCYSerine supplies the carbon of 5,10-methylene-THFFolate and methionine cyclesAlcohol dehydrogenase (ADH1B), CYP2E1ADHAldehyde dehydrogenase 2 (ALDH2)ALDH2GlycogenGlucoseGlucose-6-PFructose-6-PFructose-1,6-P₂Glyceraldehyde-3-P3-PhosphoglyceratePhosphoenolpyruvatePyruvateLactateRibulose-5-PRibose-5-PNucleotidesFructoseFructose-1-PDHAPGlycerolGlycerol-3-PFatty acyl-CoAAcetyl-CoAMalonyl-CoAPalmitateTriacylglycerolsAcetoacetyl-CoAHMG-CoAMevalonateIsopentenyl-PPFarnesyl-PPUbiquinoneDolicholPrenylated proteinsSqualeneLanosterol7-DehydrocholesterolCholesterolBile acidsSteroid hormonesVitamin D₃Fatty acyl-CoAAcetyl-CoAKetone bodiesOxaloacetateCitrateIsocitrateα-KetoglutarateSuccinyl-CoASuccinateFumarateMalateIQIIIcIVATP synthaseGlutamateNH₄⁺ + HCO₃⁻Carbamoyl-PCitrullineArgininosuccinateArginineOrnithineUreaEthanolAcetaldehydeAcetateAlanineSerineFolic acidTHF5,10-CH₂-THF5-CH₃-THFHomocysteineMethionineSAMSAH

Point at a pathway to see its name. Double arrows mark reversible steps; dotted arrows mark the steps that run backwards when the liver makes glucose.

  • Sugars
  • Fats and cholesterol
  • Energy
  • Amino acids
  • Folate and B12
  • Alcohol
  • Where a medicine acts