S1 Nuclease is non-specific endonuclease from Aspergillus oryzae, active primarily on single-stranded DNA and RNA. S1 Nuclease catalyzes degradation of single-stranded nucleic acids into oligonucleotides and 5’-mononucleotides. Double-stranded DNA, double-stranded RNA and DNA-RNA hybrids are resistant to degradation at moderate enzyme concentration. S1 Nuclease is capable of cleavage of double-stranded nucleic acids at nicks, mismatches and small gaps.