Transport of Stachyose and Sucrose by Vacuoles of Japanese Artichoke (Stachys sieboldii) Tubers
Year: 1992
Type: article
Abstract: Vacuoles are the stores for large amounts of stachyose [alphagal (1,6) alphagal (1,6) alphaglc (1,2) betafru] in tubers of Japanese artichoke (Stachys sieboldii). The uptake of stachyose by these vacuoles was examined and compared with that of sucrose. The uptake mechanisms of both sugars were quite similar. The kinetics showed a single saturable response to increasing external concentrations of (14)C-sugars with similar apparent K(m) values of about 50 and 30 millimolar for stachyose and sucrose, respectively. The uptake rates, however, were always higher for stachyose than for sucrose. Stachyose and sucrose uptake was inhibited by fructose and raffinose, and, reciprocally, by sucrose and stachyose, but not by glucose or galactose. The main structural feature common to all sugars recognized by the uptake systems seems to be a terminal fructosyl residue. The uptake of both sugars was stimulated by Mg-ATP and inorganic pyrophosphate, suggesting a proton-sugar antiport system. The possibility that stachyose and sucrose might be transported by the same carrier is discussed.
Source: PLANT PHYSIOLOGY
DOI: 10.1104/pp.98.2.442
Author: Felix Keller
Institution: University of Zurich
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2032255529