Isolation of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase from Young Leaves of Phytolacca dioica L.

Aims: Ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO) catalyses a key reaction by which inorganic carbon is assimilated into organic carbon found in the biosphere. The present study was aimed to isolate this enzyme from leaves of Phytolacca dioica L.

Study Design: In this work, first crude extracts from leaves at different stages of development were assayed to isolate this enzyme, then young leaves of P. dioica were used considering high value of specific activity.

Methodology: Classical methods for protein isolation have been used to characterise RubisCO from P. dioica leaves.

Results: RubisCO was isolated from young leaves by gel-filtration. The pure RubisCO showed two predominant bands (56- and 15-kDa) by SDS-PAGE. N-terminal sequences data on large (56 kDa) and Small (15 kDa) subunits obtained by automatic Edman degradation show a high percentage of identity with large and small subunit of other RubisCo enzymes. Moreover, the N-terminal amino acid sequence obtained by Edman degradation of the expressed large subunit (56 kDa) corresponds to the traduced one found by the analysis of the chloroplast genome of P. dioica (access number AFU65422).

Conclusion: The data on RubisCO from young leaves of Phytolacca dioica L. (RubisCO-Pd), obtained in the present work, could be used as the starting point for biological characterization of this enzyme.