Two different fructokinase isoforms of Arabidopsis thaliana have been identified and characterized by non-denaturing electrophoresis followed by activity-staining. The two fructokinases, fructokinase1 (FRK1) and fructokinase2 (FRK2), showed a high specificity for fructose and did not stain when glucose or mannose were used as substrate. Fructose and ATP at high concentrations (above 5 mM) induced a substrate inhibition of the two enzymatic activities. Arabidopsis FRK1 and FRK2 were capable of employing GTP, CTP, UTP and TTP as phosphate donors, although with a significantly lower efficiency than ATP. The two fructokinase activities were also activated by K+, at around 10-20 mM, and inhibited by ADP and AMP at concentrations above 10 mM. Finally, FRK1 and FRK2 showed a different expression pattern in the plant, with FRK1 being more abundant in the roots and FRK2 in the shoots. The results demonstrate a simple technique that provides important information about fructokinase activities in the plants and which can be useful for the analysis of Arabidopsis mutants. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

CHARACTERIZATION OF TWO ARABIDOPSIS THALIANA FRUCTOKINASES

PISTELLI, LAURA;ALPI, AMEDEO
2001

Abstract

Two different fructokinase isoforms of Arabidopsis thaliana have been identified and characterized by non-denaturing electrophoresis followed by activity-staining. The two fructokinases, fructokinase1 (FRK1) and fructokinase2 (FRK2), showed a high specificity for fructose and did not stain when glucose or mannose were used as substrate. Fructose and ATP at high concentrations (above 5 mM) induced a substrate inhibition of the two enzymatic activities. Arabidopsis FRK1 and FRK2 were capable of employing GTP, CTP, UTP and TTP as phosphate donors, although with a significantly lower efficiency than ATP. The two fructokinase activities were also activated by K+, at around 10-20 mM, and inhibited by ADP and AMP at concentrations above 10 mM. Finally, FRK1 and FRK2 showed a different expression pattern in the plant, with FRK1 being more abundant in the roots and FRK2 in the shoots. The results demonstrate a simple technique that provides important information about fructokinase activities in the plants and which can be useful for the analysis of Arabidopsis mutants. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.
Gonzali, S.; Pistelli, Laura; De bellis, L.; Alpi, Amedeo
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/177233
Citazioni
  • ???jsp.display-item.citation.pmc??? 10
  • Scopus 37
  • ???jsp.display-item.citation.isi??? 35
social impact