Partial purification and characterization of fructokinase from developing taproots of sugar beet (Beta vulgaris)

Crystal structure of a fructokinase homolog from Halothermothrix orenii

“…This reaction is particularly important in sink tissues where sucrose assimilation, degradation and conversion to starch is mediated by invertase and/or sucrose synthase (SS), and the fructose produced must be phosphorylated to maintain the carbon flux to starch or respiration. FRKs are widely reported to have a preference for ATP over other nucleotides and unless in the presence of high GTP or UTP concentrations, ATP will be the principle source of phosphate (Chaubron et al, 1995;Martinez-Barajas et al, 1997). The activity of FRK greatly exceeding glucokinase in many tissues is consistent with the view that SS, rather than invertase, is the major route of sucrose degradation, thus producing a larger amount of fructose than glucose.…”

Divergent Fructokinase Genes Are Differentially Expressed in Tomato

“…Fructokinase has been purified from developing potato tubers (Gardner et al, 1992), sugar beet taproots (Chaubron et al, 1995), and tomato fruit (Martinez-Barajas and Randall, 1996) Enzyme activity was measured in the presence of 2 mM sugar. A transformant with pFL61 was used as a control.…”

“…Fructokinase has been characterized from some sink tissues such as potato (Solanum tuberosum) tubers (Gardner et al, 1992;Renz and Stitt, 1993), pea seeds (Copeland et al, 1978), taproots of sugar beet (Chaubron et al, 1995), avocado fruit (Copeland and Tanner, 1988), maize kernels (Doehlert, 1990), and tomato fruit (Martinez-Barajas and Randall, 1996). In potato tubers a cDNA encoding fructokinase has been cloned and its physiological role in starch synthesis has been investigated (Taylor et al, 1995).…”

Purification and characterization of a glucokinase from young tomato ( Lycopersicon esculentum L. Mill.) fruit

“…The functional form is most probably a homodimer with subunits of 30±40 kDa (Chaubron et al 1995;MartinezBarajas and Randall 1996). Fructokinases isolated from dierent sources have K m values for Fru ranging from 41 to 201 lM, are extremely speci®c for Fru and most exhibit substrate inhibition at physiological Fru concentrations, i.e.…”

“…Plant tissues usually contain multiple FKs with native molecular masses ranging from 70±85 kDa (Copeland et al 1984;Chaubron et al 1995;Martinez-Barajas and Randall 1996) to 102±105 kDa . The functional form is most probably a homodimer with subunits of 30±40 kDa (Chaubron et al 1995;MartinezBarajas and Randall 1996).…”