Types of Restriction Endonuclease enzymes

These are the types in the cutting of DNA fragments into pieces.

1. T Y P E S OF R E S T R I C T I O N E N Z Y M E S Nishanth Sekar

2. RESTRICTION ENZYMES Produces by bacterial cells to protect themselves against the foreign in bided DNA There are three major activities of RE’s: Recognition Digestion (or) Modify ( Methylase ) There are two types of methylase : dAM (A residue) dCM (C residue) Nishanth Sekar

3. TYPES OF RE Depending upon the source of isolation & the biochemical activity , RE’s are of THREE groups. [ The first enzyme discovered which recognizes a given sequence is known as the prototype. ] Isoschizomer Neoschizomer Isocaudomer Nishanth Sekar

4. Isoschizomer Pairs of restriction enzymes isolated from two different sources having exactly the same recognition site and also exactly the same digestion/cleavage site . SphI (CGTAC/G) and BbuI (CGTAC/G) are isoschizomers S1 S2 D R Nishanth Sekar

5. Neoschizomer Pairs of restriction enzymes isolated from two different sources having exactly the same recognition site but the site of digestion/cleavage of S1 and S2 varies .   Smal (CCC/GGG ) and XmaI (C/CCGGG) are neoschizomers . S1 S2 D 1 R D 2 Nishanth Sekar

6. Isocaudomer Pairs of restriction enzymes isolated from two different sources having different recognition site but the digestion site for S1 & S2 is exactly the same . Produces compatible ends (having similar type of ends) Mbo I and BamH I are isocaudomers . S1 S2 R 2 D R 1 Nishanth Sekar

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