Which enzyme shows greatest substrate specificity

Options

A. Nuclease
B. Trypsin
C. Pepsin
D. Sucrase.

Answer

### Step-by-Step Solution:

1. **Understanding Enzyme Specificity**: Enzymes are biological catalysts that speed up chemical reactions in the body. Each enzyme has a specific substrate (the molecule it acts upon). The degree of substrate specificity varies among different enzymes.

2. **Analyzing the Options**:
- **Nuclease**: This enzyme acts on nucleic acids (DNA and RNA). It does not show high specificity because it can act on various types of nucleic acids.
- **Trypsin**: This is a proteolytic enzyme that breaks down proteins. It can act on many different proteins, indicating low specificity.
- **Pepsin**: Similar to trypsin, pepsin is also a proteolytic enzyme that digests proteins. It acts on a variety of protein substrates, thus showing low specificity.
- **Sucrase**: This enzyme specifically catalyzes the hydrolysis of sucrose into glucose and fructose. It acts only on sucrose, demonstrating high substrate specificity.

3. **Identifying the Correct Answer**: Among the given options, sucrase is the only enzyme that shows high substrate specificity as it acts solely on sucrose. Therefore, the correct answer is **Sucrase**.

### Final Answer:
The enzyme that shows the greatest substrate specificity is **Sucrase**.

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