Protein Expression and Purification, Vol.19, No.3, 411-418, 2000
Overexpression in Escherichia coli and characterization of the chloroplast fructose-1,6-bisphosphatase from wheat
An important Calvin cycle enzyme, chloroplast fructose-1,6-bisphosphatase (FBPase) from wheat, has been cloned and expressed up to 15% of the total cell protein using a pPLc expression vector in Escherichia coli by replacing the codons in the 5'-terminal encoding sequence with optimal and AT-rich ones, The overexpressed wheat FBPase is soluble, fully active, and heat stable, It can be purified by chromatography in turn on DEAE-Sepharose and Sephacryl S-200, and around 15 mg of purified enzymes (>96%) is obtained from 1 liter of cultured bacteria. Its special activity is 8.8 u/mg, K-cat is 22.9/S, K-m is 121 mu M, and V-max is 128 mu mol/min.mg, The recombinant FBPase can be activated by DTT, Na+, or low concentrations of Li+, Ca2+, Zn2+, QuHCl, and urea, while it can be inhibited by K+ Or NH4+.