Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain, in contrast to exonucleases, which cleave phosphodiester bonds at the end of a polynucleotide chain. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a Phosphate group and two other Molecules over two Exonucleases are enzymes (found as individual enzymes or as parts of larger enzyme complexes that cleave Nucleotides one at a time from an end of a polynucleotide chain Restriction endonucleases (Restriction Enzymes) cleave DNA at specific sites, and are divided into three categories, Type I, Type II, and Type III, according to their mechanism of action. A restriction enzyme (or restriction Endonuclease) is an Enzyme that cuts double-stranded DNA at specific recognition Nucleotide These enzymes are often used in genetic engineering to make recombinant DNA for introduction into bacterial, plant, or animal cells.

Common endonucleases:

Restriction endonucleases (ENases) are products of bacteria, and can be used to map a piece of DNA.

Bacterial:

1. UvrABC endonuclease is a well documented endonuclease found in E. UvrABC endonuclease is a multienzyme complex in Ecoli bacteria involved in DNA repair mechanism by Nucleotide excision repair and it is therefore sometimes coli.

See also

• Exonuclease
• Nuclease
• Ribonuclease

Exonucleases are enzymes (found as individual enzymes or as parts of larger enzyme complexes that cleave Nucleotides one at a time from an end of a polynucleotide chain A nuclease is an Enzyme capable of cleaving the Phosphodiester bonds between the nucleotide subunits of Nucleic acids Older papers may use terms such as Ribonuclease, abbreviated commonly as RNase, is a Nuclease that catalyzes the degradation of RNA into smaller components

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