IUBMB Enzyme Nomenclature

EC 4.2.2.17

Accepted name: inulin fructotransferase (DFA-I-forming)

Reaction: Produces α-D-fructofuranose β-D-fructofuranose 1,2':2,1'-dianhydride (DFA I) by successively eliminating the diminishing (2→1)-β-D-fructan (inulin) chain from the terminal D-fructosyl-D-fructosyl disaccharide.

For diagram click here.

Other name(s): inulin fructotransferase (DFA-I-producing); inulin fructotransferase (depolymerizing, difructofuranose-1,2':2',1-dianhydride-forming); inulin D-fructosyl-D-fructosyltransferase (1,2':1',2-dianhydride-forming); inulin D-fructosyl-D-fructosyltransferase (forming α-D-fructofuranose β-D-fructofuranose 1,2':1',2-dianhydride); 2,1-β-D-fructan lyase (α-D-fructofuranose-β-D-fructofuranose-1,2':2,1'-dianhydride-forming)

Systematic name: (2→1)-β-D-fructan lyase (α-D-fructofuranose-β-D-fructofuranose-1,2':2,1'-dianhydride-forming)

Comments: This enzyme, like EC 4.2.2.16 [levan fructotransferase (DFA-IV-forming)] and EC 4.2.2.18 [inulin fructotransferase (DFA-III-forming)] 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 common name. Since the transfer is intramolecular, the reaction is an elimination and, hence, the enzyme is a lyase, belonging in EC 4.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 125008-19-7

References:

1. Seki, K., Haraguchi, K., Kishimoto, M., Kobayashi, S. and Kainuma, K. Purification and properties of a novel inulin fructotransferase (DFA I-producing) from Arthrobacter globiformis S14-3. Agric. Biol. Chem. 53 (1989) 2089-2094.

[EC 4.2.2.17 created 1992 as EC 2.4.1.200, transferred 2004 to EC 4.2.2.17]


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