Restriction enzymes are nucleases too equally they cutting at an internal set of deoxyribonucleic acid (and non an end) they are known equally endonucleases. They are also known equally molecular knives, molecular scissors, restriction enzymes or molecular scalpels.
The sequence recognised past times the restriction enzyme to cutting the deoxyribonucleic acid is called restriction site, recognition site or restriction endonuclease site. The recognition site consists of 4-8 base of operations pairs.
Types of restriction enzymes : The restriction endonucleases are grouped into iii types. - Type I Restriction Endonuclease:
- Type II Restriction Endonuclease
- Type III Restriction Endonuclease
Type I Restriction Endonuclease vs Type II Restriction Endonuclease
Type I Restriction Endonuclease | Type II Restriction Endonuclease |
These are close complex. The enzyme is made upwardly of iii non identical subunits. | These are simplest.The enzyme is made upwardly of 2 identical sub units. |
Molecular weight is 4,00,000 daltons. | Molecular weight ranges from 20,000 to 1,00,000 daltons. |
The site of cutting is 1,000 nucleotides away from the recognition site. | The site of cutting is inward the same recognition site. |
The sequence of cutting is non specific. | The sequence of cutting is specific.
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The enzymes protect DNAs past times methylation. | No methylation activity. |
ATP, Mg2+ too adenosyl methionine are required for activation. | Mg2+ lonely is required for activated |
The enzyme has both endonuclease action too methylase activity. | Restriction action alone. |
Examples: EcoK, EcoB | Examples: Hind II, EcoRI, |
Type II restriction endonucleases are close of import tools inward factor cloning.
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