The enzyme responsible for oxidative decarboxylation of pyruvate to acetyl Co-A is
(a) Hexokinase
(b) Succinic dehydrogenase
(c) Pyruvate dehydrogenase
(d) RUBP carboxylase / oxygenase

Options

A. Hexokinase
B. Succinic dehydrogenase
C. Pyruvate dehydrogenase
D. RUBP carboxylase / oxygenase

Answer

To solve the question regarding the enzyme responsible for the oxidative decarboxylation of pyruvate to acetyl CoA, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Process**: The question refers to the conversion of pyruvate (a 3-carbon molecule) into acetyl CoA (a 2-carbon molecule). This process is known as oxidative decarboxylation and is a crucial step that occurs after glycolysis.

2. **Identify the Reaction**: This reaction is often referred to as the transition reaction or link reaction. It takes place in the mitochondria and involves the removal of a carbon dioxide molecule from pyruvate and the addition of coenzyme A to form acetyl CoA.

3. **Determine the Enzyme Involved**: The enzyme that catalyzes this reaction is known as pyruvate dehydrogenase. This enzyme facilitates the conversion of pyruvate to acetyl CoA while also producing NADH.

4. **Evaluate the Options**:
- (a) **Hexokinase**: This enzyme is involved in the first step of glycolysis, converting glucose to glucose-6-phosphate. It is not involved in the conversion of pyruvate to acetyl CoA.
- (b) **Succinic dehydrogenase**: This enzyme is part of the Krebs cycle (citric acid cycle) and is not responsible for the oxidative decarboxylation of pyruvate.
- (c) **Pyruvate dehydrogenase**: This is the correct enzyme that catalyzes the oxidative decarboxylation of pyruvate to acetyl CoA.
- (d) **RUBP carboxylase/oxygenase**: Also known as Rubisco, this enzyme is involved in the Calvin cycle of photosynthesis and is not related to the conversion of pyruvate.

5. **Conclusion**: Based on the evaluation of the options, the correct answer is (c) **Pyruvate dehydrogenase**.

### Final Answer:
(c) Pyruvate dehydrogenase