Heterogeneity of DNA-methylases from Escherichia coli CK cells
Nikol'skaia, I.I.; Lopatina, N.G.; Debov, S.S.
Biokhimiia 45(8): 1457-1462
1980
ISSN/ISBN: 0320-9725 PMID: 7016199 Document Number: 160791
The existence of five DNA methylases, differing in their specificity towards the methylated sequence, in the cells of E. coli CK has been demonstrated. Two enzymes methylate cytosine to form 5'-methylcytosine, while three enzymes methylate adenine to form 6'-methylaminopurine. A method consisting in simultaneous isolation of five individual enzymes, which involves gel-filtration of the protein fraction with 0.3-0.6 M ammonium sulfate on Biogel A-05AM, is proposed.