PEP carboxylase is an enzyme that catalyzes the addition of carbon dioxide to phosphoenolpyruvate (PEP) to form oxaloacetate, a four-carbon compound. This reaction is crucial in the carbon fixation process, particularly within C4 plants and CAM plants. Its action helps these plants efficiently capture carbon dioxide for photosynthesis, especially under conditions of drought, high temperatures, and low atmospheric CO2 concentrations.
