[Isolation and fractionation of DNA methylases from Mycobacterium butyricum]

Properties of total preparation of methylases from M. butyricum strain were studied using various methods of column chromatography. Distinct heterogeneity of the methylase preparation was demonstrated by gel filtration, anion exchange chromatography on diethyl aminoethyl cellulose and affinity chromatography on Sepharose blue. Several methylases, dissimilar both in physico-chemical properties and in their specificity to nitrogenous bases, were found in M. butyricum cells. In the strain studied methylases of adenine and cytosine were found, which were responsible for biosynthesis of 6-methyl adenine and 5-methyl cytosine in the acceptor DNA at the ratio 9 : 1.