THE MECHANISM OF RUBISCO ACTIVASE - INSIGHTS FROM STUDIES OF THE PROPERTIES AND STRUCTURE OF THE ENZYME

Rubisco, the primary carboxylating enzyme in photosynthesis, must be a ctivated to catalyze CO2 fixation. The concept of an 'activase', a spe cific protein for activating Rubisco, was first introduced in 1985 bas ed largely on biochemical and genetic studies of a high CO2-requiring mutant of Arabidopsis (Salvucci et al. (1985) Photosynth Res 7: 193-20 1). Over the past ten years, details about the occurrence, structure, and properties of Rubisco activase have been elucidated. However, the mechanism of action of Rubisco activase remains elusive. This review d iscusses the need for and function of Rubisco activase and summarizes information about the properties and structure of Rubisco activase. Th e information is evaluated in the context of the mechanism of Rubisco activase.