Question

Why is PEP carboxylase better than RuBisCO?

Answer 1

PEP carboxylase:

1. PEP (Phosphoenolpyruvate) carboxylase is the first enzyme in the C4 or Hatch Slack pathway for carbon fixation.
2. It catalyzes the conversion of phosphoenolpyruvate (PEP) to oxaloacetic acid (OAA), the 4C acid, by adding CO₂.
3. RuBisCO is an enzyme involved in the first major step of carbon fixation, the process by which plants and other photosynthetic organisms transform atmospheric carbon dioxide into energy-rich molecules.
4. PEP carboxylase is a mesophyll cell enzyme that catalyzes carbon fixation in C4 plants.
5. In comparison to RuBisCO, it has a stronger affinity for CO2 and lacks oxygenase activity.
6. As a result, unlike RuBisCO, there is no loss of efficiency due to photorespiration.
7. In an oxygen-rich environment, PEP carboxylase outperforms RuBisCO.