Restriction Enzymes and DNA

Enzymes and Restriction Endonucleases

• In 1963, two enzymes responsible for restricting the growth of bacteriophage in Escherichia coli were isolated.
• One of these enzymes added methyl groups to DNA, while the other cut DNA, known as a restriction endonuclease.

Hind II Restriction Endonuclease

• Hind II was the first restriction endonuclease to be isolated and characterized in 1968, five years after the initial discovery.
• Hind II functions by recognizing a specific DNA nucleotide sequence and cutting DNA molecules at a particular point.
• The specific base sequence recognized by Hind II is known as the recognition sequence.

Restriction Enzymes

• Over 900 restriction enzymes have been isolated from more than 230 strains of bacteria.
• Each of these enzymes recognizes different recognition sequences.
• The convention for naming these enzymes is based on the genes and species of the prokaryotic cell from which they were isolated.
• Example: EcoRI comes from Escherichia coli RY 13, with the letter ‘R’ derived from the name of the strain.

This quiz is about the discovery of restriction enzymes in E. coli, specifically the Hind II enzyme, which cuts DNA at a specific sequence. It covers the history and function of restriction endonucleases.