Question

Which of the following is a restriction endonuclease ?

• A. Protease
• B. DNase I
• C. RNase I
• D. Hind II

Answer 1

The Correct Option is D

To determine which of the given options is a restriction endonuclease, let's first understand the concept of restriction endonucleases.

Restriction Endonucleases: These are enzymes that cut DNA at specific sequences, known as recognition sites. They are essential tools in molecular biology for DNA manipulation and are used in various techniques, such as cloning and analysis of DNA fragments.

Now, let's evaluate each option:

1. Protease: Proteases are enzymes that break down proteins by hydrolyzing peptide bonds. They do not interact with DNA, so they are not restriction endonucleases.
2. DNase I: This enzyme nonspecifically degrades DNA into smaller fragments. It is not sequence-specific and therefore not a restriction endonuclease.
3. RNase I: RNase I is an enzyme that degrades RNA. Like proteases and DNase I, it is not involved in the targeted cutting of DNA at specific sequences, so it cannot be considered a restriction endonuclease.
4. Hind II: Hind II is, in fact, a restriction endonuclease. It specifically cuts DNA at particular sequences, making it highly valuable for molecular biology applications. This enzyme was one of the first restriction endonucleases to be discovered and characterized, marking a significant advancement in genetic research.

Therefore, after examining all the options, it is clear that the enzyme Hind II is the correct answer, as it fits the definition and role of a restriction endonuclease.