The Nuclease S1 enzyme from Aspergillus oryzae has the ability to degrade single-stranded oligonucleotides composed of either deoxynucleotides or ribonucleotides.

Nuclease S1 from Aspergillus oryzae has been used in a study to assess a biochemical method for mapping mutational alterations in DNA. It has also been used in a study to investigate the DNA damage and repair in a γ-irradiated rat brain tumor.

Nuclease S1 isolated from Aspergillus oryzae exhibits endo- and exolytic hydrolytic activity for the phosphodiester bonds of single-stranded DNA and RNA yielding 5′-phosphomononucleotide and 5′-phosphooligonucleotide end-products. It is used to digest non-annealed polynucleotide tails and hairpin loops in RNA and DNA duplexes and can be used to convert superhelical DNA to the linear form.

SI nuclease from Aspergillus oryzae can generate double-stranded DNA breaks in response to DNA nicks or abasic sites.

One unit will cause 1.0 microgram of single-stranded nucleic acid to become perchloric acid soluble per minute at pH 4.6 at 37°C.

Solution containing 30 mM sodium acetate, 50 mM NaCl, 1 mM ZnCl₂, 50% glycerol, 2 mg/ml protein