Low temperature regulates sucrose-phosphate synthase activity in Colobanthus quitensis (Kunth) Bartl. by decreasing its sensitivity to Pi and increased activation by glucose-6-phosphate

Bascunan-Godoy, L; Uribe, E; Zuniga-Feest, A; CORCUERA, LJ; Bravo, LA

Abstract

Colobanthus quitensis (Kunth) Bartl. is widely distributed from Mexico to the Antarctic. C. quitensis is a freezing resistant species that accumulates sucrose in response to cold. We tested the hypothesis that low temperature modifies the kinetic properties of C. quitensis sucrose phosphate synthase (SPS) to increase its activity and ability to synthesize sucrose during cold acclimation. Cold acclimation caused a fourfold increment in sucrose concentration and a 100% increase in SPS activity, without changes in the level of SPS protein. Cold acclimation did not affect the optimal temperature and pH for SPS activity. However, it caused a tenfold increase in the inhibition constant (K i) for inorganic phosphate (Pi) calculated as a function of fructose-6-phosphate (Fruc-6-P). SPS from cold acclimated plants also exhibited a higher reduction of its Michaelis constant (K m) for glucose-6-phosphate (Gluc-6-P) with respect to non-acclimated plants. We suggest that the increase in C. quitensis SPS K i for Pi and the increase in activation by Gluc-6-P in response to cold keep SPS activated, leading to high sucrose accumulation. This may be an important adaptation that allows efficient accumulation of sucrose during the harsh Antarctic summer. © 2006 Springer-Verlag.

Más información

Título según WOS: Low temperature regulates sucrose-phosphate synthase activity in Colobanthus quitensis (Kunth) Bartl. by decreasing its sensitivity to Pi and increased activation by glucose-6-phosphate
Título según SCOPUS: Low temperature regulates sucrose-phosphate synthase activity in Colobanthus quitensis (Kunth) Bartl. by decreasing its sensitivity to Pi and increased activation by glucose-6-phosphate
Título de la Revista: POLAR BIOLOGY
Volumen: 29
Número: 12
Editorial: Springer
Fecha de publicación: 2006
Página de inicio: 1011
Página final: 1017
Idioma: English
URL: http://link.springer.com/10.1007/s00300-006-0144-3
DOI:

10.1007/s00300-006-0144-3

Notas: ISI, SCOPUS