[The method of isolation of Sau 6782-type methylases]

Heterogeneous profile of methylases was found in S. aureus 6782 strain. A procedure was developed for isolation of individual methylases from Sau 6782 free of Sau 6782 restrictases and unspecific nucleases by means of hydrophobic chromatography on phenyl-Sepharose. Ion exchange, affinity chromatographies and gel filtration were also used for isolation of the Sau 6782 methylases. But this technique was of limited suitability for isolation of individual methylating enzymes of the Sau 6782 type because it did not allow to separate completely these methylases from contaminating enzymes of DNA degradation. Effects of salts, glycerol and Triton X-100 on activity of total preparation of methylases Sau 6782 were studied. Na+ and K+ chlorides, ammonium sulfate at concentrations 0.4 M and highen as well as Triton X-100 inhibited reversibly the methylase activity followed by complete reduction up to initial level after dialysis. Glycerol at concentration 60% activated Sau 6782 methylases by 50% and stabilized the enzyme.