On the Two Deoxyribonucleases, K1 and K2, Isolated from Mycelia of Aspergillus oryzae

V. Piece-Meal Hydrolysis of Native DNA Effected by DNase K2

Abstract

Bacillus subtilis DNA was digested with DNase K2 [EC 3. 1. 4. 5] in the absence of MgSO₄. Under the conditions used, the digestion proceeded slowly and the products consisted mainly of DNA segments with long chain lengths. After fractionation on a DEAE-cellulose column, the average chain length was estimated from the sizes of DNA appeared on electron-microscopic photographs. The DNA segments isolated from a fraction and purified by the gel filtration were found to be of comparatively homo-geneous size (500-1000 nucleotides in pairs).