Question

Which of the following enzymes is used for carboxylation of RuDP?

• A. Ribulose transaminase
• B. Ribulose biphosphatase transaminase
• C. Ribulose diphosphate carboxylase
• D. Peroxidase

Answer 1

Answer: (C)

Ribulose diphosphate carboxylase

Transaminase enzymes catalyze the transfer of an alpha amino group of one amino acid to carbonyl acid; these enzymes do not catalyze carboxylation. Ribulose 1,5-diphosphate carboxylase/oxygenase (RUBISCO) catalyzes the covalent attachment of CO${}_2$ to ribulose 1,5-bisphosphate followed by cleavage of the unstable six-carbon intermediate to form two molecules of 3-phosphoglycerate. Peroxidases are scavenging enzymes that catalyze the degradation of hydrogen peroxide into water and oxygen. Thus, the correct answer is option C.