[Isolation and properties of two DNA-polymerases from Bacillus stearothermophilus cells].

Two DNA-polymerases (1 and 2) were isolated from the cells of Bacillus stearothermophilus and their properties were investigated. The isolation procedure included separation of nucleic acids on DEAE-cellulose, affinity chromatography on DNA-agarose and chromatography on DEAE-Sephadex. DNA-polymerase 1 was purified 150-fold; its molecular weight and pH optimum are 135 000 and 7.3, respectively. DNA-polymerase 2 was purified 1000-fold; its molecular weight and pH optimum are 95 000 and 9.0, respectively. Both DNA polymerases differ considerably in their affinities for DNA-agarose and DEAE-Sephadex. Purification of DNA-polymerase 1 resulted in a loss of the enzyme thermal stability and its conversion into a labile enzyme with the temperature optimum at 40 degrees. DNA-polymerase 2 retained its high thermal stability after purification. The DNA activated by DNAase 1 was found to be the most effective primer matrix for the both enzymes. In contrast to DNA-polymerase 2, DNA-polymerase 1 is sensitive to the effects of SH-group blockers and high salt concentrations and is activated 1.5 -- 2-fold by 10% ethanol.