First restriction endo nuclease enzyme was-

Concept-

• Restriction enzymes belong to a larger class of enzymes called nucleases.
• Restriction enzymes are used to break DNA molecules.
• Restriction enzymes are of three types- Exonuclease, endonuclease, and restriction endonuclease.
  • Exonuclease- They cut off nucleotides from 5' or 3' ends of DNA molecule.
  • Endonuclease- They break DNA duplex at any point except the end.
  • Restriction endonuclease- They cleave DNA duplex at specific points.

Explanation-

• Restriction endonuclease was found by Arber.
• They act as "molecular scissors".
• They recognize the base sequence at palindrome sites in the DNA duplex and cut its strands.
• Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated.
• It was found that Hind II always cut DNA molecules at a particular point by recognizing a specific sequence of six base pairs.
• This specific base sequence is known as the recognition sequence for Hind II.

The first restriction endonuclease-Hind II.

Additional Information