Purification and characterization of fructose-2,6-bisphosphatase, a substrate-specific cytosolic enzyme from leaves.
Fructose-2,6-bisphosphatase (EC 3.1.3.46), which hydrolyzes fructose 2,6-bisphosphate to fructose 6-phosphate and Pi, has been purified to apparent homogeneity from spinach leaves and found to be devoid of fructose-6-phosphate,2-kinase activity. The isolated enzyme is a dimer (76 kDa determined by gel filtration) composed of two 33-kDa subunits. The enzyme is highly specific and displays hyperbolic kinetics with its fructose 2,6-bisphosphate substrate (Km = 32 microM). The products of the reaction, fructose 6-phosphate and Pi, along with AMP and Mg2+ are inhibitors of the enzyme. Nonaqueous cell fractionation revealed that, like the fructose 2,6-bisphosphate substrate, fructose-2,6-bisphosphatase as well as fructose-6-phosphate,2-kinase occur in the cytosol of spinach leaves.
Macdonald
F D
FD
Division of Molecular Plant Biology, University of California, Berkeley 94720.
Chou
Q
Q
Buchanan
B B
BB
Stitt
M
M
D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000201:enzymology; D007202:Indicators and Reagents; D007700:Kinetics; D008970:Molecular Weight; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification* / Q000378:metabolism; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
D007202:Indicators and Reagents; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases