Characterization of two Arabidopsis thaliana fructokinases

Citation
S. Gonzali et al., Characterization of two Arabidopsis thaliana fructokinases, PLANT SCI, 160(6), 2001, pp. 1107-1114
Citations number
22
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT SCIENCE
ISSN journal
01689452 → ACNP
Volume
160
Issue
6
Year of publication
2001
Pages
1107 - 1114
Database
ISI
SICI code
0168-9452(200105)160:6<1107:COTATF>2.0.ZU;2-1
Abstract
Two different fructokinase isoforms of Arabidopsis thaliana have been ident ified and characterized by non-denaturing electrophoresis followed by activ ity-staining. The two fructokinases, fructokinase1 (FRK1) and fructokinase2 (FRK2), showed a high specificity for fructose and did not stain when gluc ose or mannose were used as substrate. Fructose and ATP at high concentrati ons (above 5 mM) induced a substrate inhibition of the two enzymatic activi ties. Arabidopsis FRK1 and FRK2 were capable of employing GTP, CTP, UTP and TTP as phosphate donors, although with a significantly lower efficiency th an ATP. The two fructokinase activities were also activated by K+, at aroun d 10-20 mM, and inhibited by ADP and AMP at concentrations above 10 mM. Fin ally, FRK1 and FRK2 showed a different expression pattern in the plant, wit h FRK1 being more abundant in the roots and FRK2 in the shoots. The results demonstrate a simple technique that provides important information about f ructokinase activities in the plants and which can be useful for the analys is of Arabidopsis mutants. (C) 2001 Elsevier Science Ireland Ltd. All right s reserved.