《英文msh詞典》Modification Methylases,DNA
[入口詞] Modification Methylases,DNA
[主題詞] DNA Modification Methylases
[英文釋義] Enzymes that are part of the restriction-modification systems. They are responsible for producing a species-characteristic methylation pattern,on either adenine or cytosine residues,in a specific short base sequence in the host cell's own DNA. This methylated sequence will occur many times in the host-cell DNA and remain intact for the lifetime of the cell. Any DNA from another species which gains entry into a living cell and lacks the characteristic methylation pattern will be recognized by the restriction endonucleases of similar specificity and destroyed by cleavage. Most have been studied in bacterial systems,but a few have been found in eukaryotic organisms.