Question

In $C_4$ pathway, $C{O}_2$ fixation in mesophyll cells is carried out by the enzyme

• A. PEP carboxylase
• B. Pyruvate dehydrogenase
• C. RuBisCO
• D. Pyruvate decarboxylase

Answer 1

The correct option is A PEP carboxylase

A) PEP carboxylase is the primary acceptor of carbon dioxide and fixes it.
B) Pyruvate dehydrogenase is used in the citric acid cycle to convert pyruvic acid to Acetyl CoA.

C) RuBisCO is involved in $C_3$ plants.
D) Pyruvate decarboxylase is an enzyme that catalyses the decarboxylation of pyruvic acid to acetaldehyde.

So the correct answer is 'PEP carboxylase'.