Restriction enzyme: The enzyme which is used to dissect the particular part of a DNA is said to be Restriction Enzyme. They are used to assist insertion of genes into plasmid vectors during gene cloning and protein production experiments.
Examples: Alul, HaeIII, BamHI, Eco-RL, HindIII etc.
More than 400 restriction enzymes have been isolated from the bacteria that manufacture them. In live bacteria, restriction enzymes function to defend the cell against invading viral bacteriophages. There are three classes of restriction enzymes, designated types I, II, and III.