Purification and characterization of a recombinant pea cytoplasmic fructose-1,6-bisphosphatase

Full-length cDNA encoding pea cytoplasmic fructose-1,6-bisphosphatase (cyFBPase) was cloned from a pea cDNA library. The cloned cDNA was introduced into the Escherichia coli expression vector pET-15b. The recombinant cyFBPase was expressed in E. coli BL21 (DE3) cells in a soluble form and purified to homogeneity by Ni(+)-NTA affinity chromatography. The identity of the recombinant cyFBPase was confirmed by SDS-PAGE and immunoblot analysis using a polyclonal anti-His tag antibody. The recombinant cyFBPase was active at neutral pH ranges (6.6-9.0) and thermostable as other cyFBPases. The activation energy (E(a)) and Arrhenius frequency factor were 17.4 kcal/mol and 2.6 x 10(12)/s, respectively. The K(M) and V(max) values of the recombinant enzyme were calculated as 10.47 microM and 109 micromol/min, respectively. In case of removal of histidine tag, the K(M) value was calculated as 5.03 microM. The recombinant enzyme was non-competitively and competitively inhibited by AMP and fructose-2,6-bisphosphate, respectively.