The enzyme that is not found in a `C_(3)` plant is

Options

A. RuBP carboxylase
B. PEP carboxylase
C. NADP reductase
D. ATP synthase

Explanation

To determine which enzyme is not found in C3 plants, we can analyze the given options:

1. **IUBP Carboxylase**: This enzyme, also known as RuBisCO (Ribulose bisphosphate carboxylase/oxygenase), is crucial for the Calvin cycle in C3 plants. It catalyzes the first step of carbon fixation by converting ribulose bisphosphate (RuBP) and carbon dioxide into 3-phosphoglycerate (3-PGA). Therefore, this enzyme is present in C3 plants.

2. **PEP Carboxylase**: This enzyme is primarily found in C4 plants. It catalyzes the fixation of carbon dioxide into a 4-carbon compound (oxaloacetate) during the initial steps of photosynthesis. Since PEP carboxylase is not involved in the C3 pathway, it is the enzyme that is not found in C3 plants.

3. **NADP Reductase**: This enzyme plays a role in the electron transport chain during photosynthesis, specifically in the reduction of NADP+ to NADPH. It is present in both C3 and C4 plants, so it is not the correct answer.

4. **ADP Synthetase**: This enzyme is involved in the synthesis of ATP from ADP and inorganic phosphate. It is also present in both C3 and C4 plants, thus it is not the correct answer.

Based on the analysis above, the enzyme that is not found in C3 plants is **PEP Carboxylase**.

**Final Answer**: PEP Carboxylase