Purification and Further Properties of Single‐Strand‐Specific Nuclease from <i>Aspergillus oryzae</i>

TLDR

The nuclease is useful for measuring annealing of labeled DNA. A simple purification scheme was devised to isolate Aspergillus nuclease S1 from commercial crude amylase powder. Purification yielded 90 % pure enzyme with a 27 % overall yield, and the metalloprotein (32 kDa) is strictly single‑strand‑specific, degrades both DNA and RNA, has a sharp pH optimum at 4.2, and remains active in low dodecylsulfate concentrations.

Abstract

A simple scheme has been devised for the purification of Aspergillus nuclease S 1 from commercially available crude amylase powder. Five purification steps yield 90% pure nuclease with an overall yield of 27%. The enzyme is shown to be absolutely specific for single‐stranded nucleic acids. It degrades both DNA and RNA. The nuclease exhibits a sharp pH optimum at pH 4.2 and is active in low concentrations of dodecylsulfate. Aspergillus nuclease S 1 is a metalloprotein of molecular weight 32000. The utility of this nuclease for measuring annealing of labeled DNA is discussed.