1fructosyltransferase

1-fructosyltransferase, abbreviated 1-FFT, is an enzyme that catalyzes the transfer of a fructosyl unit from a donor molecule to an acceptor molecule, resulting in the elongation or remodeling of fructan polymers. The primary activity is believed to transfer a fructosyl moiety from one fructan chain to another, thereby extending inulin-type fructan chains that consist mainly of β(2→1) linkages. In some plant species, 1-FFT can contribute to the diversification of fructan structures by altering chain length and branching patterns.

Distribution and function. 1-FFT is associated with plants that accumulate fructans as storage carbohydrates, notably members of the Asteraceae such as chicory and Jerusalem artichoke, as well as other species in which fructan metabolism has been studied. It is part of a broader fructan biosynthesis pathway that includes related enzymes such as 1-SST (sucrose:sucrose 1-fructosyltransferase) and 6-SFT (sucrose:fructan 6-fructosyltransferase). Together, these enzymes regulate the initiation, elongation, and modification of fructan polymers, which serve as carbon reserves and may play roles in stress tolerance.

Biochemical properties. 1-FFT enzymes are glycosyltransferases that operate under physiological conditions compatible with plant metabolism. They typically act on sugar donors and acceptors related to fructan metabolism and give rise to polymers with characteristic fructan linkages. The precise substrate specificities and kinetic parameters can vary among species and enzyme isoforms.

Applications and research. Understanding 1-FFT contributes to the broader study of carbohydrate storage in plants and has potential applications in agricultural productivity and industrial production of fructans and prebiotics. Further characterization and cloning of 1-FFT genes support comparative analyses across fructan-accumulating species.