[Relations between the condition of growth and activity of DNA-methylases of Mycobacteria butyricum].

Conditions for cultivation of Mycobacteria butiricum were studied. Optimal conditions were selected to maintain maximal rate of DNA-metylase activity keeping of unspecific nuclease activity in cells at a low level. Analyses of plots of the time- dependent DNA methylation by the enzymes, isolated from bacterial preparations cultivated under various conditions (solid and liquid synthetic and organic media with earation and without of it), demonstrated that aeration and organic medium were the deciding conditions responsible for high level of the methylase activity. The shape of plot of DNA methylation by the enzymes from M. butiricum was similar irrespective of the conditions of cultivation--maximal rate of methylation occurred within 2-3 hrs of incubation and was maintained within 22 hrs. The stable content of methylated DNA-acceptor, within long-term periods of incubation, correlated with the low level of nucleases since viscosity of DNA from Cd phage was unaltered after incubation with the enzyme preparation from M. butiricum. The M. butiricum strain appears to be valuable for identification of restrictases.