Restriction enzyme was discovered by

Options

A. Alexander Fleming
B. Smith and Nathans
C. Berg
D. Waksman

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the discovery of restriction enzymes. It's essential to identify who was responsible for this discovery.

2. **Analyzing the Options**:
- **Option 1: Alexander Fleming**: He is known for discovering penicillin, not restriction enzymes. Therefore, this option is incorrect.
- **Option 2: Smith and Nathans**: This is the correct answer. They discovered and characterized restriction enzymes, specifically Type II restriction enzymes, in the late 1960s and early 1970s.
- **Option 3: Bug**: This refers to Herbert Boyer, who is known for his work in gene splicing and recombinant DNA technology, but not for the discovery of restriction enzymes.
- **Option 4: Voxman**: He is known for discovering streptomycin and other antibiotics, not restriction enzymes.

3. **Conclusion**: After analyzing the options, the correct answer is **Smith and Nathans**.

4. **Additional Information**: Type II restriction enzymes are derived from bacteria, specifically from *Haemophilus influenzae*. This discovery was significant for molecular biology and biotechnology.

**Final Answer**: The restriction enzyme was discovered by **Smith and Nathans**.

---