title: Regulation of the activation of chloroplast fructose-1,6-bisphosphatase: inhibition by spermidine and spermine.
abstract: The activation of chloroplast fructose-1,6-bisphosphatase by fructose-1,6-bisphosphate, Ca2+, DTT and chloroplast thioredoxin-f is prevented by either spermidine or spermine; on the contrary, other amino compounds do not replace polyamines in this reversible effect. On the other hand, neither spermidine nor spermine modify the catalysis of chloroplast fructose-1,6-bisphosphatase. The effect of spermidine, but not the effect of spermine, is reversed by increasing the concentration of Ca2+ in the activation; higher concentrations of Fructose-1,6-bisphosphate or thioredoxin-f do not restore the control activity. The present results suggest that other regulatory mechanisms may control the activation of fructose-1,6-bisphosphatase in chloroplasts.
mesh_terms: D002118:Calcium / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation; D006597:Fructose-Bisphosphatase / Q000378:metabolism*; D013095:Spermidine / Q000494:pharmacology*; D013096:Spermine / Q000494:pharmacology*
chemical_list: D013096:Spermine; D006597:Fructose-Bisphosphatase; D002118:Calcium; D013095:Spermidine