Fig. 3.

Effect of RCA concentration on RCA activity. Tobacco Rubisco in the ER form was incubated with the indicated concentrations of tobacco RCA at 30 °C in the presence of 5 mM ATP. Rubisco activity was measured continuously as described in Fig. 2 and the fraction of sites activated was determined at each time point. From a linear regression of the progress curve, RCA activity was determined at each concentration of RCA as the fraction of Rubisco sites activated min⁻¹ (filled circle). The specific activity of RCA, mol Rubisco sites activated min⁻¹ mol⁻¹ RCA protomer (open squares), was calculated using these rates and the amounts of Rubisco and RCA protein in the assays