PureRec Duplex-Specific Nuclease (DSN) is an endonuclease that selectively digests double-stranded DNA (dsDNA) and DNA in DNA-RNA hybrids, exhibiting virtually no activity towards single-stranded DNA (ssDNA) or RNA. It can discriminate between perfectly matched and non-matched short DNA duplexes. To catalyze cleavage, DSN needs a minimum of 10 bp dsDNA or 15 bp perfectly matched DNA-RNA duplex. This enzymatic function is reliant upon the presence of Mg^2+ ions, with a recommended concentration of 5 mM for most applications. PureRec DSN is overexpressed and extensively purified from a non-animal source and is free of non-specific nucleases or RNases.