Studies on chromatin-associated nuclease from barley leaves

摘要

A nuclease associated with the chromatin of barley leaves has been solubilized and purified 20 fold. The purified preparation hydrolyzes native or denatured DNA and RNA, but exhibits no phosphodiesterase or phosphomonoesterase activity. The ratios of RNase and DNase activities remain essentially constant throughout all the steps of purification. The two enzyme activities had pH optimum of 7.0 and showed similar effects of phosphate, Zn++, Mg++and other metal cations, EDTA, inhibitors, freezing and thawing, heat treatment and precipitation by protamine sulfate and streptomycin sulfate. RNA and DNA were degraded by the enzyme in endonucleolytic fashion.