Ambion™ Escherichia coli ribonuclease III (RNase III; EC 3.1.24) is a dual Stranded RNA (dsRNA)-specific exonuclease. InE. coli , RNase III cleaves ribosomal RNA (rRNA) precursors during rRNA maturation. The enzyme cleaves dsRNA into 12–15 bp dsRNA fragments with 2–3 nucleotide 3' overhangs, 5' phosphate, and 3' hydroxyl termini. Therefore, the ends and overhangs of the RNase III cleavage product are identical to those generated by Dicer in the eukaryotic RNAi pathway. RNase III cleavage product transfection can be used to induce RNAi in mammalian cells (patent pending).

Unit Definition:
One unit is defined as the catalytic cleavage of 1 µg of 500 bp dsRNA substrate to approximately 12–30 bp in 60 min at 37°C. Amount of enzyme required for fragmentation.