title: [Isolation and properties of DNA-cytosine-methylase I from Escherichia coli MRE 600].
abstract: DNA-cytosine-methylase I was isolated and purified to homogeneity. The yield made up to about 30% of total activity. The enzyme molecular weight as determined by centrifugation in a sucrose gradient, by gel filtration and by electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate was found to be 45,000. The Michaelis constant was 1,8 . 10(-6) M for SAM and 2 . 10(-4) M for DNA. DNA-cytosine-methylase I modifies phage lambda DNA in 60 sites. This modification does not protect DNA from the effects of restriction endonucleases HpaII and BsuRI. The enzyme methylates DNA in the nucleotide sequence: 5'...Pur-MC-C-G-G-Pyr...3'.
mesh_terms: D004248:DNA (Cytosine-5-)-Methyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D004279:DNA, Viral; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008780:Methyltransferases / Q000302:isolation & purification*; D008970:Molecular Weight; D013379:Substrate Specificity
chemical_list: D004279:DNA, Viral; D008780:Methyltransferases; D004248:DNA (Cytosine-5-)-Methyltransferases
vernacular_title: Vydelenie i svoĭstva DNK-tsitozin-menilazy I iz Escherichia coli MRE600.