Restriction enzyme

• Enzyme produced by bacteria as defense mechanism against viral genome by cutting of the DNA of phase and hence inactivating it.
• They are also called as biological scissors.

Types of restriction enzyme

a) Type I: Recognize specific sequence; cuts everywhere.

b) Type II: Recognize specific sequence; cleavage.

c) Type III: Between type I and II.

Palindromes:

• Sequence recognized by restriction enzyme.
• Eg: 5’GACGTC3– restriction enzyme –>’3’CTGCAG5’