Restriction endonuclease-
These are DNA cutting enzymes within a particular sequence after recognition ,as they are often cut within the dna so called restriction endonuclease.Hamilton Smith isolated a restriction enzyme from the bacterium Haemophilous influenzae called as HindII, recognize 6 base pair dsDNA sequence.
Occurance - Found in bacteria.(source)
Function - In order to sequence DNA,it is first necessasry to cut into smaller fragments.
Types - (Acc. to their recognition and specificity of cleavage.)
1.Isoschizomer-(iso=similar ,schizomer=cleavage of Dna) Similar type of cleavage in a dna from 2 different sources. called isoschizomer.For example,
Sph I (CGTAC/G) and Bbu I (CGTAC/G) are isoschizomers of each other.Can recognize both methylated and non methylated forms.
2 .Neoschizomer-.An enzyme that recognizes the same sequence but cuts it differently( different cleavage site) is a Neoschizomer.They are a specific type (subset) of Isoschizomers. For example, S
ma I (CCC/GGG) and Xma I (C/CCGGG) are neoschizomers of each other.
3. Isocaudamer-An enzyme that recognizes slightly different sequence, but produces the same ends is a isocaudamer.
Recognition sites are same for ( isoschizomer & neoschizomer ). All are isolated from 2 different sources.In isocaudamer recognition sites are different but the product is with similar type of ends.
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These are DNA cutting enzymes within a particular sequence after recognition ,as they are often cut within the dna so called restriction endonuclease.Hamilton Smith isolated a restriction enzyme from the bacterium Haemophilous influenzae called as HindII, recognize 6 base pair dsDNA sequence.
Occurance - Found in bacteria.(source)
Function - In order to sequence DNA,it is first necessasry to cut into smaller fragments.
Types - (Acc. to their recognition and specificity of cleavage.)
1.Isoschizomer-(iso=similar ,schizomer=cleavage of Dna) Similar type of cleavage in a dna from 2 different sources. called isoschizomer.For example,
Sph I (CGTAC/G) and Bbu I (CGTAC/G) are isoschizomers of each other.Can recognize both methylated and non methylated forms.
2 .Neoschizomer-.An enzyme that recognizes the same sequence but cuts it differently( different cleavage site) is a Neoschizomer.They are a specific type (subset) of Isoschizomers. For example, S
ma I (CCC/GGG) and Xma I (C/CCGGG) are neoschizomers of each other.
Image source credit http://sivabio.50webs.com/dna%20cl48.gif
3. Isocaudamer-An enzyme that recognizes slightly different sequence, but produces the same ends is a isocaudamer.
Recognition sites are same for ( isoschizomer & neoschizomer ). All are isolated from 2 different sources.In isocaudamer recognition sites are different but the product is with similar type of ends.
Thank you for visiting my blog.Please feel free to share your comment on this article ,Please subscribe and share the articles to get more such articles.
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