Activity of ribulose 1,5-bisphosphate carboxylase oxygenase as a function of storage conditions.

Optimal storage conditions to retain ribulose 1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activity were investigated. The soluble spinach (Spinacia oleracea) enzyme was pretreated with its activators, Mg(2+) and HCO(3) (-), and then stored for up to 30 days at 4 or -18 degrees C or in liquid N(2). Cold inactivation and conformational changes were suggested to be involved during Rubisco storage in the cold, leading to its inactivation. Pretreatment of the enzyme with Mg(2+) and CO(2) and subsequent storage at either 4 degrees C or in liquid N(2) or flushing the samples with N(2) and rapid freezing and storage in liquid N(2) are recommended as storage procedures. These storage treatments will prevent inactivation, so that full original specific activity will be preserved.