Levansucrase

Levansucrase is an enzyme Catalyzing transfer of the Fructose moiety of Sucrose to Polyfructose (a levan), releasing D-Glucose.

• AKA: Sucrose 6-Fructosyltransferase, Beta-2,6-Fructosyltransferase.
• Context:
  • It participates in Starch and Sucrose Metabolism.
• Example(s):
  • Pseudomonas syringae pv. glycinea http://www.uniprot.org/uniprot/O52408
  • PMID 9726857: “The EPS levan is synthesized by the extracellular enzyme levansucrase in Pseudomonas syringae, Erwinia amylovora , and other bacterial species . The lsc genes encoding levansucrase from P. syringae pv. glycinea PG4180 and P. syringae pv. phaseolicola NCPPB 1321 were cloned, and their nucleotide sequences were determined ”
• Counter-Example(s):
  • PMID 9726857: “Levansucrase was not secreted into the supernatant but was located in the periplasmic fraction of E. coli harboring the lsc gene .Expression of lsc was found to be dependent on the vector-based Plac promoter, indicating that the native promoter of lsc was not functional in E. coli .Insertion of an antibiotic resistance cassette in the lsc gene abolished levan synthesis in E. coli .A PCR screening with primers derived from lsc of P. syringae pv. glycinea PG4180 allowed the detection of this gene in a number of related bacteria .”
• See: Pseudomonas syringae pv. glycinea.

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References

2009

• (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Levansucrase
  • In enzymology, a levansucrase (EC 2.4.1.10) is an enzyme that catalyzes the chemical reaction
    • sucrose + (2,6-beta-D-fructosyl)n \rightleftharpoons glucose + (2,6-beta-D-fructosyl)n+1
  • Thus, the two substrates of this enzyme are sucrose and (2,6-beta-D-fructosyl)n, whereas its two products are glucose and (2,6-beta-D-fructosyl)n+1.

    This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is sucrose:2,6-beta-D-fructan 6-beta-D-fructosyltransferase. Other names in common use include sucrose 6-fructosyltransferase, beta-2,6-fructosyltransferase, and beta-2,6-fructan:D-glucose 1-fructosyltransferase. This enzyme participates in starch and sucrose metabolism and two-component system - general.

• Gene Ontology http://amigo.geneontology.org/cgi-bin/amigo/term-details.cgi?term=GO:0050053&session_id=7072amigo1246349584
  • Accession: GO:0050053
  • Ontology: molecular function
  • Synonyms
    • exact: beta-2,6-fructan:D-glucose 1-fructosyltransferase activity
    • exact: beta-2,6-fructosyltransferase activity
    • exact: sucrose 6-fructosyl transferase activity
    • exact: sucrose 6-fructosyltransferase activity
    • exact: sucrose:2,6-beta-D-fructan 6-beta-D-fructosyltransferase activity
  • Definition
    • Catalysis of the reaction: sucrose + 2,6-beta-D-fructosyl(n) = glucose + 2,6-beta-D-fructosyl(n+1). [source: EC:2.4.1.10, MetaCyc:LEVANSUCRASE-RXN]

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