modification methylase

modification methylase

(1) Site-specific DNA-methyltransferase (adenine-specific), EC 2.1.1.72. 
(2) Site-specific DNA-methyltransferase (cytosine-specific), EC 2.1.1.73.
(3) Site-specific DNA-methyltransferase (cytosine-N4-specific), EC 2.1.1.113.
 
Modification methylases comprise a large group of enzymes which, in conjunction with the site-specific enzymes listed as EC 3.1.21.3, EC 3.1.21.4 and EC 3.1.21.5, forms "restriction modification systems” (see there).