MetaCyc Enzyme: hexulose-6-phosphate synthase

Gene: rmpA Accession Number: G-3185 (MetaCyc)

Synonyms: HPS, 3-hexulose-6-phosphate synthase

Species: Mycobacterium gastri MN19

Subunit composition of hexulose-6-phosphate synthase = [RmpA]2
         hexulose-6-phosphate synthase subunit = RmpA

Hexulose-6-phosphate synthase (HPS) is one of the key enzymes of the ribulose-5-monophosphate (RuMP) pathway for formaldehyde assimilation. It is also a key enzyme of the related cyclic formaldehyde oxidation (dissimilatory) pathway which is often found in the organisms that poccess the RuMP cycle.
The gene encoding 3-hexulose-6-phosphate synthase is usually present in the same operon as the gene encoding 6-phospho-3-hexuloisomerase, the other key enzyme of the RuMP pathway.

Gene Citations: [Mitsui00]

Locations: cytosol

Molecular Weight of Polypeptide: 24 kD (experimental) [Kato90 ]

Molecular Weight of Multimer: 43 kD (experimental) [Kato90]

Relationship Links: Entrez-Nucleotide:PART-OF:AB034913

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Cellular Component: GO:0005829 - cytosol [Kato90]

MultiFun Terms: metabolism carbon utilization carbon compounds

Enzymatic reaction of: hexulose-6-phosphate synthase

EC Number:

hexulose 6-phosphate <=> D-ribulose 5-phosphate + formaldehyde

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the opposite direction.

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

Cofactors or Prosthetic Groups: Mn2+ [Kato90], Mg2+ [Kato90]

Inhibitors (Competitive): EDTA [Kato90]

Inhibitors (Unknown Mechanism): tiron [Kato90] , o-phenanthroline [Kato90]

Kinetic Parameters:

Km (μM)

pH(opt): 7.5 [Kato90]


Kato90: Kato N (1990). "3-Hexulose-6-phosphate synthase from Mycobacterium gastri MB19." Methods Enzymol 188;397-401. PMID: 2280712

Mitsui00: Mitsui R, Sakai Y, Yasueda H, Kato N (2000). "A novel operon encoding formaldehyde fixation: the ribulose monophosphate pathway in the gram-positive facultative methylotrophic bacterium Mycobacterium gastri MB19." J Bacteriol 182(4);944-8. PMID: 10648518

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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
Page generated by SRI International Pathway Tools version 19.0 on Fri Oct 9, 2015, biocyc12.