What does Rubisco produce when it reacts with CO2 and RuBP?

When Rubisco catalyzes the reaction between carbon dioxide (CO2) and ribulose bisphosphate (RuBP), it produces 3-phosphoglycerate (3-PGA). This occurs in the first step of the Calvin cycle, which is a critical pathway for photosynthesis in plants.

Once CO2 is fixed into an organic molecule, Rubisco facilitates the conversion of RuBP into an unstable six-carbon intermediate that quickly splits into two molecules of 3-PGA. This three-carbon compound, 3-PGA, is an essential precursor for the synthesis of glucose and other carbohydrates. The subsequent steps in the Calvin cycle involve the reduction of 3-PGA into glyceraldehyde-3-phosphate (G3P), but the immediate product of Rubisco's action is indeed 3-PGA.

Understanding this process is essential because it highlights the role of Rubisco as a central enzyme in photosynthesis, responsible for the initial fixation of atmospheric CO2 into a form that can be utilized by living organisms.