Enzyme required in early CO₂ fixation in C₄ cycle is

The enzyme required in early CO₂ fixation in the C₄ cycle is PEP carboxylase.
PEP carboxylase, which is located in the mesophyll cells, is an essential enzyme in C₄ plants.
It is an enzyme in the family of carboxy-lyases found in plants and some bacteria that catalyzes the addition of bicarbonate (HCO₃^-) to phosphoenolpyruvate (PEP) to form the four-carbon compound oxaloacetate and inorganic phosphate.