Activation of wheat chloroplast sedoheptulose bisphosphatase: a continuous spectrophotometric assay.
IE Woodrow, DA Walker
Arch Biochem Biophys | Published : 1982
A new continuous spectrophotometric assay for sedoheptulose 1,7-bisphosphatase, applied to studies of the activation and steady-state kinetics of the wheat enzyme, is described. The assay enzyme sequence couples the formation of sedoheptulose 7-phosphate to the oxidation of NADH. The recycling of the reaction substrate enables measurements to be made at essentially constant substrate concentrations. Activation of wheat chloroplast sedoheptulose 1,7-bisphosphatase required a reducing agent and could be described by a first-order rate constant. The rate of activation was greatly increased in the presence of Mg2+ and sedoheptulose 1,7-bisphosphate. The Km of the activated enzyme for sedoheptulo..View full abstract