Partial purification and characterisation of cytosolic Fructose-1, 6-bisphosphatase from Drymaria cordata

Drymaria cordata is an important ethnomedicinal plant from which many important secondary metabolites have been reported. Partial purification of the enzyme, fructose 1,6-bisphosphatase was carried out following the methods of homogenization, streptomycin sulphate precipitation, ammonium sulphate cut and molecular sieve chromatography through Bio-Gel A-0.5m column. Biochemical characterization experiments were performed by standard methods with the enzyme preparation as purified from the column. Cytosolic fructose 1,6-bisphosphatase from the leaves of Drymaria cordata was purified to about 27-fold with 77% of recovery over homogenate fraction. The enzyme was highly specific to D-fructose-1,6-bisphosphate. With increase of protein concentration upto 300µg and incubation time upto120 minutes, the enzyme activity increased linearly. The metal ions Mg 2+ or Mn 2+ strongly stimulated the enzyme activity on the other hand Li + , Hg 2 + and Zn 2+ were potent inhibitors. The D. cordata enzyme showed temperature maxima at 40˚C while the optimum pH was at 8.0. The K m value of the enzyme for its substrate, Fructose 1,6-bisphosphate was 1.11µM proving its strong affinity.