interconversion of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate is catalysed by which enzyme ?

Options

A. Phosphotriose isomerase
B. Phosphoexose isomerase
C. Phosphoglyceromutase
D. Triose kinase

Answer

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the enzyme that catalyzes the interconversion between glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP).

2. **Identify the Reaction**: This interconversion is a reversible reaction that occurs during glycolysis, which is the metabolic pathway that converts glucose into pyruvate, producing energy in the form of ATP.

3. **Analyze the Options**: The given options are:
- A) Phosphotriose isomerase
- B) Phosphohexose isomerase
- C) Phosphoglyceromutase
- D) Triose kinase

4. **Evaluate Each Option**:
- **Option A: Phosphotriose isomerase**: This enzyme specifically catalyzes the interconversion between G3P and DHAP. It is the correct answer.
- **Option B: Phosphohexose isomerase**: This enzyme catalyzes the conversion of glucose-6-phosphate to fructose-6-phosphate, which involves six-carbon sugars, not three-carbon sugars. Hence, it is not the correct answer.
- **Option C: Phosphoglyceromutase**: This enzyme catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, which is unrelated to the interconversion of G3P and DHAP. Thus, it is incorrect.
- **Option D: Triose kinase**: This enzyme is involved in the phosphorylation of triose sugars but does not catalyze the interconversion of G3P and DHAP. Therefore, it is also incorrect.

5. **Conclusion**: The enzyme that catalyzes the interconversion of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate is **Phosphotriose isomerase** (Option A).