In the Hatch & Slack cycle, the enzyme required to convert pyruvate into phosphoenol pyruvate is

Options

A. Pyruvate dehydrogenase
B. PEP carboxylase
C. Phosphoenol pyruvate dikinase
D. Phosphoenol pyruvate kinase

Answer

To solve the question regarding the enzyme required to convert pyruvate into phosphoenolpyruvate in the Hatch & Slack cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The Hatch & Slack cycle, also known as the C4 pathway, occurs in the chloroplasts of C4 plants. It is a crucial part of photosynthesis that helps in the fixation of carbon dioxide.

**Hint**: Remember that the Hatch & Slack cycle is specific to C4 plants and involves unique enzymes.

2. **Identify the Reaction**: In this cycle, pyruvate is converted into phosphoenolpyruvate (PEP). This conversion is a key step in the pathway.

**Hint**: Focus on the substrates involved in the conversion process.

3. **Determine the Enzyme**: The enzyme responsible for converting pyruvate into phosphoenolpyruvate is known as phosphoenolpyruvate dikinase (PPDK). This enzyme catalyzes the reaction and requires ATP for the conversion.

**Hint**: Look for enzymes that specifically act on pyruvate and PEP in the context of the C4 pathway.

4. **Evaluate the Options**: The options given are:
- Pyruvate dehydrogenase
- PEP carboxylase
- Phosphoenolpyruvate dikinase
- Phosphoenolpyruvate kinase

Among these options, only phosphoenolpyruvate dikinase (PPDK) is the correct enzyme that catalyzes the conversion of pyruvate to phosphoenolpyruvate.

**Hint**: Eliminate options that are known to function in other metabolic pathways, such as cellular respiration.

5. **Conclusion**: The correct answer is phosphoenolpyruvate dikinase (PPDK).

### Final Answer:
The enzyme required to convert pyruvate into phosphoenolpyruvate in the Hatch & Slack cycle is **phosphoenolpyruvate dikinase (PPDK)**.