Why is the RuBisCo enzyme more appropriately called RUBP Carboxylase -Oxygenase, and what important role does it play in photosynthesis?
The RuBisCo enzyme possesses an affinity for oxygen as well as carbon dioxide. However, the binding reaction depends on the level of concentration of oxygen and carbon dioxide. Due to this fact, it can act like a carboxylase as well as an oxygenase. Therefore, it is often called the RUBP Carboxylase-Oxygenase compound.
In C3 plants, the RuBisCo enzyme helps in binding with the carbon dioxide molecule and results in the production of 3PGA. Some of the enzyme molecules also bind with oxygen resulting in the production of phosphoglycerate and phosphoglycerate. These are formed during the process of photorespiration. This process, in turn, decreases the carbon fixation in C3 plants.
RuBisCo enzyme plays an essential role in C4 plants as well. Due to the increased concentration of carbon dioxide, the production of oxaloacetic acid is catalyzed with the help of this enzyme. Carbon fixation becomes more efficient since the process of photorespiration is prevented.