[A new method of isolation and purification of SsoII restriction endonuclease]. / Novye sposob vydeleniia i ochistki éndonukleazy restriktsii SsoII.

A new method for isolation and purification of restriction endonuclease SsoII which results in a homogeneous preparation suitable for all types of fine physico-chemical assays has been elaborated. The procedure includes four chromatographic steps: fractionation on butyl-Toyopearl, combined chromatography on SP-Toyopearl and phosphocellulose PII, and chromatography on DEAE-Toyopearl and on QAE-Toyopearl. The use of fast flow sorbents (Toyopearl) makes it possible to reduce the time needed for the separation of proteins and to optimize the fractionation conditions, thus avoiding the dialysis between the chromatographic steps which significantly decreased the enzyme activity yields in previous purification schemes. The isolation of restriction endonuclease SsoII by the new method usually takes four days.

[Isoelectric focusing of methylation and restriction enzymes from Staphylococcus aureus strain 6782]. / Izoélektrofokusirovanie fermentov metilirovaniia i restrikstii shtamma Staphylococcus aureus 6782.

The behaviour of methylation and restriction enzymes of Staphylococcus aureus 6782 during their isoelectrofocusing on ampholinese was studied. It was found that the RSau 6782 isoenzyme is represented by two isoforms, RI and RII, with isoelectric points of 4.2 and 7.9, respectively. Data from isoelectrofocusing analysis suggest that RI and R II are devoid of relaxed specificity found in the original preparation. In was shown that the relaxed specificity is also inherent in the isoschisomeric enzyme, RSau3A. Isoelectrofocusing of the original preparation RSau3A, as in case with RSau 6782, allows the identification of two peaks, RI and RII, and the separation of each peak from the "trace" activity. Multiple forms of DNA-methylase of the Sau 6782 type are represented by four isoenzymes possessing acidic properties. The method allows one to single out from the total methylase pool a modifying methylase with p1 (3.9) is close to that of RSau 6782 and thus the enzyme cannot serve for correct separation of restriction and methylation enzymes of Sau 6782.