|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 126.96.36.199
Enzymes and Genes:
hexulose-6-phosphate synthase : hps ( Brevibacillus brevis S1 )
hexulose-6-phosphate synthase : rmpA ( Mycobacterium gastri MN19 )
hexulose-6-phosphate synthase : rmpA ( Methylomonas aminofaciens 77a )
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, 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): 5.220001 [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 188.8.131.52, 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 184.108.40.206, 6-phospho-3-hexuloisomerase [Orita05]. This enzyme is a member of the orotidine 5'-monophosphate decarboxylase (OMPDC) suprafamily [Kato06].
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
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
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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