Solubilization of ribulose-1,5-bisphosphate carboxylase from the membrane fraction of pea leaves

The solubilization of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) from the membrane fraction was studied in whole leaf extracts and chloroplasts from pea. The amount of membrane-bound Rubisco was dependent on the pH of the chloroplastic lysate buffer. Maximum binding was found at pH 8.0, with about 8% of total leaf Rubisco being bound. The binding of Rubisco to the membranes was strong, and it was not released by repeated washing with hypotonic buffer or by changing ionic strength. Detergents such as Triton X-100, Tween 20, deoxycholate and dodecylsulfate were effective in solubilizing the membrane-bound Rubisco. Triton X-100 was most effective in the range of 0.04% to 0.2% and it solubilized Rubisco from the membrane without any decrease in enzyme activity.