Restriction enzymes

Restriction enzymes (endonuleases) are the enzymes that cut DNA at specific sequences. They have the ability to break various kinds of bonds that include

1.      Covalent bonds (within a single strand)

2.      Hydrogen bonds (between strands)

These enzymes are naturally found in different types of bacteria where these Bacteria use restriction enzymes to protect themselves from foreign DNA. Bacteria have mechanisms to protect themselves from the actions of their own restriction enzymes.

Recombinant DNA is constructed using restriction enzymes. Restriction enzymes are used scientifically in various processes e.g.

·         Determination of the size of a plasmid

·         To find out if there are any restriction sites for a particular enzyme on a piece of DNA (ex. EcoRI)

·         To find out how many restriction sites for a particular enzyme. 

·         To locate the restriction sites.