Question

Identify the correct sequence of enzymes given below which participate in regeneration phase of Calvin cycle.
1. Ribulose 5-phosphate epimerase
2. Ribulose 5-phosphate kinase
3. Transketolase
4. Triose phosphate isomerase

• A. 4, 1, 3, 2
• B. 3, 2, 4, 1
• C. 4, 3, 1, 2
• D. 2, 1, 4, 3

Answer 1

Answer: (C)

4, 3, 1, 2

1. 3- phosphoglyceraldehyde is isomerized to dihydroxyacetone phosphate in presence of enzyme Triose Phosphatase isomerase.

2. 2 mol. of Fructose-6- phosphate with 2 mol. of 3- phosphoglyceraldehyde produce 2 mol. of xylulose-5- phosphate and 2 mol. of Erythrose-4- phosphate in the presence of Transketolase enzyme.

3. 4 mol. of Xylulose- 5- phosphate isomerized to 4 mol. of Ribulose- 5 - phosphate in presence of ribulose phosphate epimerase.

4. 6 mol of Ribulose-5- phosphate are phosphorylated by 6 mol. of ATP to produce mol. of ribulose-1,5 - biphosphate in presence of enzyme phosphoribulose kinase.

Hence, the correct answer is '4,3,1,2'.