ENZYME entry: EC 4.2.2.18

Accepted Name
inulin fructotransferase (DFA-III-forming)
Alternative Name(s)
inulase II
inulinase II
inulin D-fructosyl-D-fructosyltransferase (1,2':2,3'-dianhydride- forming)
inulin D-fructosyl-D-fructosyltransferase (forming alpha-D-fructofuranose beta-D-fructofuranose 1,2':2,3'-dianhydride)
inulin fructotransferase (depolymerizing, difructofuranose- 1,2':2,3'-dianhydride-forming)
inulin fructotransferase (depolymerizing)
inulin fructotransferase (DFA-III-producing)
Reaction catalysed
Produces alpha-D-fructofuranose beta-D-fructofuranose 1,2':2,3'-dianhydride (DFA III) by successively eliminating the diminishing (2->1)-beta-D-fructan (inulin) chain from the terminal D-fructosyl-D-fructosyl disaccharide
Comment(s)
This enzyme, like EC 4.2.2.16 and EC 4.2.2.17 eliminates the fructan chain from the terminal disaccharide leaving a difructose dianhydride. These enzymes have long been known as fructotransferases, so this is retained in the description (official name). Since the transfer is intramolecular, the reaction is an elimination and, hence, the enzyme is a lyase, belonging in enzyme class 4.-.-.-. Formerly EC 2.4.1.93.
Cross-references
BRENDA	4.2.2.18
EC2PDB	4.2.2.18
ExplorEnz	4.2.2.18
PRIAM enzyme-specific profiles	4.2.2.18
KEGG Ligand Database for Enzyme Nomenclature	4.2.2.18
IUBMB Enzyme Nomenclature	4.2.2.18
IntEnz	4.2.2.18
MEDLINE	Find literature relating to 4.2.2.18
MetaCyc	4.2.2.18
Rhea expert-curated reactions	4.2.2.18

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All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.2.2.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.2.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.-.-.-