Definition: 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.
Other names Modification Methylases; DNA Modification Methyltransferases; Modification Methyltransferases, DNA; Modification Methylases, DNA; Methyltransferases, DNA Modification; Methylases, Modification; Methylases, DNA Modification
Biochem Pharmacol 28(8):1443;1979; Cancer Res 1979;39(10):3822; Cancer Res 37:1636;1977; Cancer Res 38(9):2673;1978; FEBS Lett 78(2):244;1977; JNCI 1979;63(4):1035; Neoplasma 25(4):385;1978
