Question

What was the first restriction enzyme to be discovered?

Answer 1

Restrictive enzymes:

1. A restriction enzyme is a protein that determines the size of a DNA molecule.
2. They do this by cleaving foreign DNA or repeating strands of DNA.
3. Restriction enzymes are classified according to their structure and the specificity of what they recognize.

First restriction enzyme:

1. The first restriction enzyme to be discovered by Hind II.
2. Hind II was extracted from Haemophilus influenza. Hind II can only recognize a specific site in DNA termed as a recognition site for Hind II (5'-C-A-G-C-T-G-3').
3. Each RE recognizes a short nucleotide sequence that is specific for a particular restriction endonuclease.
4. RE also adds methyl group on the adenine residue of self DNA to easily distinguish between foreign and own DNA sequences in bacteria.