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Pattern of fructan synthesized in cell‐free extracts from leaf blades of chilled Triticum aestivum
Author(s) -
BANCAL PIERRE,
GAUDILLÈRE JEAN PIERRE
Publication year - 1993
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1993.tb03827.x
Subject(s) - fructan , sucrose , invertase , food science , in vitro , biology , chemistry , botany , biochemistry
SUMMARY Fructosyltransferase activities were studied with varying concentrations of sucrose in cell‐free extracts from wheat ( Triticum aestivum L.). A C 18 ‐HPLC separation method was used to quantify the synthesized compounds individually. Hexoses and 1‐kestose were the major products at all temperatures and concentrations of sucrose. 1‐Kestose production was maximal at 25 °C, with an apparent K m of about 250 m, but competition for sucrose by invertase affected this value. Neokestose, which is not observed in vitro , and 6‐kestose were also formed in vitro , but at a much lower rate and at lower sucrose affinity than 1‐kestose synthesis. When extracts were incubated with a high initial concentration of sucrose for up to 1 d, five new fructan oligomers appeared. Four of these were also accumulated early in vitro by chilled blades, whereas the fifth belonged to the neokestose series. The rates of synthetic oligomers are compared to those in vivo. Invertase‐linked artefacts are present in wheat, but not overwhelming as they are in Lolium temulentum.