TABLE 2

Overview of enzymes involved in the classical ED pathway in Bacteria as well as in the modified ED pathway versions in Archaea

EnzymeEC no.AbbreviationReactionProtein superfamily(ies) (according to the SCOP database)Protein family(ies)Distribution
Glucose 6-phosphate dehydrogenase1.1..1.49G6PDHd-Glucose 6-phosphate + NAD(P)+d-glucono-1,5-lactone 6-phosphate + NAD(P)H + H+N-terminal domain NAD(P) binding Rossman fold like domain superfamily; C-terminal glyceraldehyde-3-phosphate dehydrogenase-like, C-terminal domain superfamilyGAPDH N-terminal domain family, glucose 6-phosphate dehydrogenase-like family (C-terminal domain)Bacteria, Eukarya
Glucose dehydrogenase1.1.1.47GDHd-Glucose + NAD(P)+d-glucono-1,5-lactone + NAD(P)H + H+N-terminal GroES-like superfamily, C-terminal NAD(P) binding Rossman fold domain superfamily (known as the MDR superfamily)Alcohol dehydrogenase, N-terminal domain-like and C-terminal domain-like (classical Rossman fold)Archaea, Bacteria
6-Phosphogluconolactonase3.1.1.31d-Glucono-1,5-lactone 6-phosphate + H2O → 6-phospho-d-gluconate
Gluconolactonase3.1.1.17d-Glucono-1,5-lactone H2O → d-gluconate
6-Phosphogluconate dehydratase4.2.1.12EDD6-Phospho-d-gluconate → 2-keto-3-deoxy-6-phospho-d-gluconate + H2OLeuD/IlvD-like superfamilyIlvD/EDD familyBacteria
Gluconate dehydratase4.2.1.39GADd-Gluconate → 2-keto-3-deoxy-d-gluconate + H2OEnolase-like N-terminal and C-terminal domain superfamilyArchaea, Bacteria
2-Keto-3-deoxy-d-gluconate kinase2.7.1.45KDGK2-Keto-3-deoxy-d-gluconate + ATP → 2-keto-3-deoxy-6-phospho-d-gluconate + ADPRibokinase superfamilyPFK-B familyBacteria, ED pathway-utilizing Archaea
2-Keto-3-deoxy-(6-phospho)-d-gluconate aldolase4.1.2.14/4.1.2.21KD(P)GA2-Keto-3-deoxy-(6-phospho)-d-gluconate ⇆ glyceraldehyde-(3-phosphate) + pyruvateAldolase superfamily [(βα)8 barrel fold]Class I aldolase family (KDG aldolase subfamily distinct from bacterial KDPG aldolases and also from class I F1,6BP aldolases and archaeal-type class I F1,6BP aldolases)Bacteria, ED pathway-utilizing Archaea
2-Keto-3-deoxy-d-gluconate aldolase4.1.2.14KDGA2-Keto-3-deoxy-d-gluconate ⇆ glyceraldehyde + pyruvateAldolase superfamily [(βα)8 barrel fold]Class I aldolase family (distinct from the KDG aldolase subfamily, bacterial KDPG aldolases, and also class I F1,6BP aldolases and archaeal-type class I F1,6BP aldolases)Thermoacidophilic Euryarchaeota, Picrophilus torridus, Thermoplasma spp.
Glyceraldehyde dehydrogenase1.2.1.3GADHGlyceraldehyde + NAD(P)+ H2O → glycerate + NAD(P)H + H+ALDH-like superfamilyThermoacidophilic Archaea
Glyceraldehyde:ferredoxin oxidoreductase1.2.99.8GAORGlyceraldehyde + Fdox + H2O → glycerate + Fdred + H+Aldehyde oxidase/xanthine dehydrogenase superfamilySulfolobus spp.
Glycerate kinase2.7.1.165GKGlycerateGckA/TtuD-like superfamily (C-terminal domain, also known as the MOFRL superfamily)GckA/TtuD-like familyEukarya, Bacteria, Archaea