IUBMB Enzyme Nomenclature

EC 2.4.1.243

Accepted name: 6G-fructosyltransferase

Reaction: [1-β-D-fructofuranosyl-(2→1)-]m+1 α-D-glucopyranoside + [1-β-D-fructofuranosyl-(2→1)-]n+1 α-D-glucopyranoside = [1-β-D-fructofuranosyl-(2→1)-]m α-D-glucopyranoside + [1-β-D-fructofuranosyl-(2→1)-]n+1 β-D-fructofuranosyl-(2→6)-α-D-glucopyranoside (m > 0; n ≥ 0)

Glossary: [1-β-D-fructofuranosyl-(2→1)-]n-α-D-glucopyranoside = inulin

Other name(s): fructan:fructan 6G-fructosyltransferase; 1F(1-β-D-fructofuranosyl)m sucrose:1F(1-β-D-fructofuranosyl)nsucrose 6G-fructosyltransferase; 6G-FFT; 6G-FT; 6G-fructotransferase

Systematic name: 1F-oligo[β-D-fructofuranosyl-(2→1)-]sucrose 6G-β-D-fructotransferase

Comments: Inulins are polysaccharides consisting of linear or branched D-fructofuranosyl chains attached to the fructosyl residue of sucrose by a β(2→1) linkage. This enzyme catalyses the transfer of the terminal (21)-linked -D-fructosyl group of an inulin chain onto O-6 position of the glucose residue of another inulin molecule [1]. For example, if 1-kestose [1F-(β-D-fructofuranosyl)sucrose] is both the donor and recipient in the reaction shown above, i.e., if m = 1 and n = 1, then the products will be sucrose and 6G-di-β-D-fructofuranosylsucrose. In this notation, the superscripts F and G are used to specify whether the fructose or glucose residue of the sucrose carries the substituent. Alternatively, this may be indicated by the presence and/or absence of primes (see 2-Carb-36.2). Sucrose cannot be a donor substrate in the reaction (i.e. m cannot be zero) and inulin cannot act as an acceptor. Side reactions catalysed are transfer of a β-D-fructosyl group between compounds of the structure 1F-(1-β-D-fructofuranosyl)m-6G-(1-β-D-fructofuranosyl)n sucrose, where m ≥ 0 and n = 1 for the donor, and m ≥ 0 and n ≥ 0 for the acceptor.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 79633-28-6

References:

1. Shiomi, N. Purification and characterisation of 6G-fructosyltransferase from the roots of asparagus (Asparagus officinalis L.). Carbohydr. Res. 96 (1981) 281-292.

2. Shiomi, N. Reverse reaction of fructosyl transfer catalysed by asparagus 6G-fructosyltransferase. Carbohydr. Res. 106 (1982) 166-169.

3. Shiomi, N. and Ueno, K. Cloning and expression of genes encoding fructosyltransferases from higher plants in food technology. J. Appl. Glycosci. 51 (2004) 177-183.

4. Ueno, K., Onodera, S., Kawakami, A., Yoshida, M. and Shiomi, N. Molecular characterization and expression of a cDNA encoding fructan:fructan 6G-fructosyltransferase from asparagus (Asparagus officinalis). New Phytol. 165 (2005) 813-824. [PMID: 15720693]

[EC 2.4.1.243 created 2006]


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