Testing and Isolation of High-Purity Restriction Endonucleases

A new method of testing restriction nucleases is proposed. This method is based on high-temperature treatment of crude cell extracts. Disrupted cells were heated at 50-60°C, centrifuged, and assayed for restrictases. This method provides the opportunity for screening new enzymes in microbial strains enriched with nonspecific restrictases. High-temperature treatment of cell extracts of certain producers reduces the number of steps of the procedure used for isolating high-purity restrictases; the resulting preparations are capable of maintaining high enzymatic activity during long-term storage. It was shown that high-temperature treatment can be applied not only to thermophilic but also to mesophilic strains of microorganisms of different taxa.[PUBLICATION ABSTRACT]