EC - 3-hexulose-6-phosphate synthase

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IntEnz Enzyme Nomenclature


Accepted name:
3-hexulose-6-phosphate synthase
Other names:
D-arabino-3-hexulose 6-phosphate formaldehyde-lyase
3-hexulosephosphate synthase
3-hexulose phosphate synthase
Systematic name:
D-arabino-hex-3-ulose-6-phosphate formaldehyde-lyase (D-ribulose-5-phosphate-forming)




Requires Mg2+ or Mn2+ for maximal activity [1]. 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 [1]. 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 [6]. This enzyme is a member of the orotidine 5'-monophosphate decarboxylase (OMPDC) suprafamily [5].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0043801
UniProtKB/Swiss-Prot: (33) [show] [UniProt]


  1. Ferenci, T., Strøm, T. and Quayle, J.R.
    Purification and properties of 3-hexulose phosphate synthase and phospho-3-hexuloisomerase from Methylococcus capsulatus.
    Biochem. J. 144 : 477-486 (1974). [PMID: 4219834]
  2. Kato, N., Ohashi, H., Tani, Y. and Ogata, K.
    3-Hexulosephosphate synthase from Methylomonas aminofaciens 77a. Purification, properties and kinetics.
    Biochim. Biophys. Acta 523 : 236-244 (1978). [PMID: 564713]
  3. Yanase, H., Ikeyama, K., Mitsui, R., Ra, S., Kita, K., Sakai, Y. and Kato, N.
    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 : 201-205 (1996). [PMID: 8595859]
  4. Yurimoto, H., Kato, N. and Sakai, Y.
    Assimilation, dissimilation, and detoxification of formaldehyde, a central metabolic intermediate of methylotrophic metabolism.
    Chem. Rec. 5 : 367-375 (2005). [PMID: 16278835]
  5. Kato, N., Yurimoto, H. and Thauer, R.K.
    The physiological role of the ribulose monophosphate pathway in bacteria and archaea.
    Biosci. Biotechnol. Biochem. 70 : 10-21 (2006). [PMID: 16428816]
  6. Orita, I., Yurimoto, H., Hirai, R., Kawarabayasi, Y., Sakai, Y. and Kato, N.
    The archaeon Pyrococcus horikoshii possesses a bifunctional enzyme for formaldehyde fixation via the ribulose monophosphate pathway.
    J. Bacteriol. 187 : 3636-3642 (2005). [PMID: 15901685]
  7. Kato, N., Miyamoto, N., Shimao, M. and Sakazawa, C.
    3-Hexulose phosphate pynthase from a new facultative methylotroph, Mycobacterium gastri MB19.
    Agric. Biol. Chem. 52 : 2659-2661 (1988).

[EC created 2008]