PARTIAL-PURIFICATION AND PROPERTIES OF DE OXYRIBONUCLEASES FROM EGGS AND LIVER OF XENOPUS-LAEVIS - COMPARISON WITH DEOXYRIBONUCLEASE-II FROM BOVINE SPLEEN

Deoxyribonucleases from eggs and the liver of Xenopus laevis were part ially purified by DEAE-cellulose and heparin-Sepharose affinity column chromatographies. The fractions having egg and liver DNase activities were eluted on high performance liquid chromatography through TSK gel G3000SW at the molecular weights of 41.5 and 45 kDa, respectively. Th e frog DNases hydrolyzed a native DNA over a heat-denatured DNA, and a lso formed double-strand cuts not only in linear A-DNA but also in clo sed circular pBR322DNA. The pH optimum of the DNases was 4.5-5.0 in 50 mM acetate buffer. These enzyme activities were abolished by treatmen t at 80 degrees C for 5 min and pH 2, 3 or 12 for Ih. The enzymes act in such a manner as deoxyribonuclease II (from bovine spleen)-type nuc lease with respect to substrate specificity, optimum pH and cation dep endence.