EC |
2.4.1.246 |
Accepted name: |
mannosylfructose-phosphate synthase |
Reaction: |
GDP-mannose + D-fructose 6-phosphate = GDP + β-D-fructofuranosyl-α-D-mannopyranoside 6F-phosphate |
Glossary: |
mannosylfructose = β-D-fructofuranosyl-α-D-mannopyranoside |
Other name(s): |
mannosylfructose-6-phosphate synthase; MFPS |
Systematic name: |
GDP-mannose:D-fructose-6-phosphate 2-α-D-mannosyltransferase |
Comments: |
This enzyme, from the soil proteobacterium and plant pathogen Agrobacterium tumefaciens strain C58, requires Mg2+ or Mn2+ for activity. GDP-mannose can be replaced by ADP-mannose but with a concomitant decrease in activity. The product of this reaction is dephosphorylated by EC 3.1.3.79 (mannosylfructose-phosphate phosphatase) to form the non-reducing disaccharide mannosylfructose, which is the major endogenous osmolyte produced by several α-proteobacteria in response to osmotic stress. The F in the product name is used to indicate that the fructose residue of sucrose carries the substituent. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 92480-04-1 (not distinguished from EC 2.4.1.167) |
References: |
1. |
Torres, L.L. and Salerno, G.L. A metabolic pathway leading to mannosylfructose biosynthesis in Agrobacterium tumefaciens uncovers a family of mannosyltransferases. Proc. Natl. Acad. Sci. USA 104 (2007) 14318–14323. [DOI] [PMID: 17728402] |
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[EC 2.4.1.246 created 2008] |
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EC |
3.1.3.79 |
Accepted name: |
mannosylfructose-phosphate phosphatase |
Reaction: |
β-D-fructofuranosyl-α-D-mannopyranoside 6F-phosphate + H2O = β-D-fructofuranosyl-α-D-mannopyranoside + phosphate |
Glossary: |
mannosylfructose = β-D-fructofuranosyl-α-D-mannopyranoside |
Other name(s): |
mannosylfructose-6-phosphate phosphatase; MFPP |
Systematic name: |
β-D-fructofuranosyl-α-D-mannopyranoside-6F-phosphate phosphohydrolase |
Comments: |
This enzyme, from the soil proteobacterium and plant pathogen Agrobacterium tumefaciens strain C58, requires Mg2+ for activity. Mannosylfructose is the major endogenous osmolyte produced by several α-proteobacteria in response to osmotic stress and is synthesized by the sequential action of EC 2.4.1.246 (mannosylfructose-phosphate synthase) followed by this enzyme. While mannosylfructose 6-phosphate is the physiological substrate, the enzyme can use sucrose 6-phosphate very efficiently. The F in mannosylfructose 6F-phosphate is used to indicate that the fructose residue of sucrose carries the substituent. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Torres, L.L. and Salerno, G.L. A metabolic pathway leading to mannosylfructose biosynthesis in Agrobacterium tumefaciens uncovers a family of mannosyltransferases. Proc. Natl. Acad. Sci. USA 104 (2007) 14318–14323. [DOI] [PMID: 17728402] |
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[EC 3.1.3.79 created 2009] |
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