Haberman A, Heywood J, Meselson M
Proc Natl Acad Sci U S A. 1972 Nov;69(11):3138-41. doi: 10.1073/pnas.69.11.3138.
The highly purified restriction endonucleases of E. coli K and coliphage P1 transfer methyl groups from S-adenosylmethionine to adenine residues of unmodified DNA. Incubation of unmodified DNA with endonucleases K or P and S-adenosylmethionine renders the DNA resistant to restriction. The enzymes, therefore, have both restriction endonuclease and modification methylase activities.
大肠杆菌K和噬菌体P1的高度纯化的限制性内切酶可将甲基基团从S-腺苷甲硫氨酸转移至未修饰DNA的腺嘌呤残基上。将未修饰的DNA与内切酶K或P以及S-腺苷甲硫氨酸一起温育会使DNA具有抗限制性。因此,这些酶同时具有限制性内切酶和修饰甲基化酶的活性。