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Grahame J. Kelly, Ute Mukherjee, Joseph A. M Holtum, Erwin Latzko, Purification, Kinetic and Regulatory Properties of Phosphofructokinase from Chiorella pyrenoidosa, Plant and Cell Physiology, Volume 26, Issue 2, March 1985, Pages 301–307, https://doi.org/10.1093/oxfordjournals.pcp.a076910
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Abstract
Phosphofructokinase was purified 585-fold from Chlorella pyrenoidosa by using a combination of ammonium sulphate fractionation, filtration through Sepharose 4B and chromatography on DEAE-Sephacel. Enzyme stability was maintained by the presence of 50 mM Pi at pH 6.6. The optimum pH for activity was 7.7. Concentrations of substrates required to achieve half maximal velocity in the standard assay were 9 μM (ATP) and 0.2 mM (fructose-6-P). ATP above 0.5 mM was inhibitory. Enzyme activity was inhibited by high concentrations (10–100 mM) of Pi but lower concentrations (1–5 mm) were effective in relieving the influence of other inhibitors such as P enolpyruvate. Inhibition by P-enolpyruvate was greater at lower pH and with less Pi in reaction mixtures: 50% inhibition could be attained with 0.1 mm P-enolpyruvate. Fructose-2,6-bisphosphate, which was shown to be present in Chlorella, had no effect on the phosphofructokinase. Chlorella appeared to contain only one form of phosphofructokinase, possibly in the chloroplast. No pyrophosphate :D-fructose-6-P 1-phospho transferase activity could be detected.
