MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Brevibacillus brevis S1: hexulose-6-phosphate synthaseInferred from experiment: hps
Methylomonas aminofaciens 77a: hexulose-6-phosphate synthaseInferred from experiment: rmpA
Mycobacterium gastri MN19: hexulose-6-phosphate synthaseInferred from experiment: rmpA

In Pathway: formaldehyde assimilation II (RuMP Cycle), formaldehyde oxidation I

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Mass balance status: Balanced.

Enzyme Commission Primary Name: 3-hexulose-6-phosphate synthase

Enzyme Commission Synonyms: D-arabino-3-hexulose 6-phosphate formaldehyde-lyase, 3-hexulosephosphate synthase, 3-hexulose phosphate synthase, HPS

Standard Gibbs Free Energy (ΔrG in kcal/mol): 5.220001Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
Requires Mg2+ or Mn2+ for maximal activity [Ferenci74a]. The enzyme is specific for formaldehyde and D-ribulose 5-phosphate as substrates. Ribose 5-phosphate, xylulose 5-phosphate, allulose 6-phosphate and fructose 6-phosphate cannot act as substrate. This enzyme, along with EC, 6-phospho-3-hexuloisomerase, plays a key role in the ribulose monophosphate cycle of formaldehyde fixation, which is present in many microorganisms that are capable of utilizing C1-compounds [Ferenci74a]. The hyperthermophilic and anaerobic archaeon Pyrococcus horikoshii OT3 constitutively produces a bifunctional enzyme that sequentially catalyses the reactions of this enzyme and EC, 6-phospho-3-hexuloisomerase [Orita05]. This enzyme is a member of the orotidine 5'-monophosphate decarboxylase (OMPDC) suprafamily [Kato06].

Citations: [Yurimoto05, Yanase96, Kato78]

Gene-Reaction Schematic

Gene-Reaction Schematic

Unification Links: KEGG:R05338, Rhea:25201

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:


Ferenci74a: Ferenci T, Strom T, Quayle JR (1974). "Purification and properties of 3-hexulose phosphate synthase and phospho-3-hexuloisomerase from Methylococcus capsulatus." Biochem J 144(3);477-86. PMID: 4219834

Kato06: Kato N, Yurimoto H, Thauer RK (2006). "The physiological role of the ribulose monophosphate pathway in bacteria and archaea." Biosci Biotechnol Biochem 70(1);10-21. PMID: 16428816

Kato78: Kato N, Ohashi H, Tani Y, Ogata K (1978). "3-Hexulosephosphate synthase from Methylomonas aminofaciens 77a. Purification, properties and kinetics." Biochim Biophys Acta 523(1);236-44. PMID: 564713

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Orita05: Orita I, Yurimoto H, Hirai R, Kawarabayasi Y, Sakai Y, Kato N (2005). "The archaeon Pyrococcus horikoshii possesses a bifunctional enzyme for formaldehyde fixation via the ribulose monophosphate pathway." J Bacteriol 187(11);3636-42. PMID: 15901685

Yanase96: Yanase H, Ikeyama K, Mitsui R, Ra S, Kita K, Sakai Y, Kato N (1996). "Cloning and sequence analysis of the gene encoding 3-hexulose-6-phosphate synthase from the methylotrophic bacterium, Methylomonas aminofaciens 77a, and its expression in Escherichia coli." FEMS Microbiol Lett 135(2-3);201-5. PMID: 8595859

Yurimoto05: Yurimoto H, Kato N, Sakai Y (2005). "Assimilation, dissimilation, and detoxification of formaldehyde, a central metabolic intermediate of methylotrophic metabolism." Chem Rec 5(6);367-75. PMID: 16278835

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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