Which of the following is a restriction endonuclease?

Options

A. Lipase
B. Amylase
C. Alul
D. Anhydrase

Answer

To determine which of the following is a restriction endonuclease, we will analyze each option provided:

1. **Lipase**: This enzyme is responsible for breaking down fats (lipids). Since it does not act on DNA, it is not a restriction endonuclease.

2. **Amylase**: This enzyme helps in the breakdown of carbohydrates, specifically starch into sugars. Like lipase, it does not act on DNA, so it is also not a restriction endonuclease.

3. **ALU-1**: This is a specific type of restriction endonuclease. Restriction endonucleases are enzymes that cut DNA at specific sequences. ALU-1 recognizes a specific DNA sequence and cleaves it, making it a restriction enzyme.

4. **Anhydrase**: This enzyme, such as carbonic anhydrase, is involved in the conversion of carbon dioxide and water to bicarbonate and protons. It does not act on DNA, hence it is not a restriction endonuclease.

From the analysis above, the only enzyme that qualifies as a restriction endonuclease is **ALU-1**.

### Final Answer:
The correct answer is **ALU-1**.