Question

In sugar cane plant carbon is fixed in malic acid, in which the enzyme that fixes $C{O}_2$ is

• A. Ribulose biphophate carboxylase
• B. Phospoenol pyruvate carboxylase
• C. Ribulose phosphate kinase
• D. Fructose phosphatase

Answer 1

The correct option is B Phospoenol pyruvate carboxylase

The sugar cane plant is a $C_4$ plant meaning that first stable product is a compound having four carbon atoms. In these plants the initial carbon dioxide fixation is carried out by the enzyme phosphoenol pruvate carboxylase or PEP carboxylase, in the mesophyll cells of leaves. The reaction is carboxylation of phosphoenol pyruvate into four carbon atoms containing organic acids like oxalo acetic acid and malic acid.