Question

What are the functions of the enzymes isolated by Stewart Linn and Werner Arber?

Answer 1

Stewart Linn and Werner Arber isolated modification enzymes known as methylase and restriction enzymes. Restriction endonucleases are classified into four groups - Types I, Type II, Type III, and Type IV.

Step by step answer: The findings of restriction enzyme began with a hypothesis, but later it was confirmed by Stewart Linn and Werner Arber in the late 1960s when they actually isolated a modification enzyme called methylase and a restriction enzyme. The growth of bacteriophage is restricted by these enzymes. Protective methyl groups were added to the DNA by using the methylase enzyme and the restriction enzyme is used for cutting unmethylated DNA at multiple locations along its length into segments. The restriction enzymes selectively cut up foreign DNA in a process called restriction digestion inside a prokaryote at the same time host DNA is protected by a modification enzyme that modifies the prokaryotic DNA and blocks cleavage. These two processes are collectively known as restriction-modification systems.
Additional information: Restriction endonucleases are further classified into four groups. They are as follows: Types I, Type II, Type III, and Type IV. Analyzing the DNA sequence indicates that there are more than four types of restriction enzymes. Specific short DNA sequences are recognized by all types of enzymes that carry out the endonucleolytic cleavage of DNA to give specific fragments with terminal 5'-phosphates. However, they differ in their recognition sequence.

Note: The restriction enzymes are also called restriction endonuclease or restrictase. These enzymes are widely used for DNA modification in laboratories, and they are an important tool in molecular cloning.