Ambion™ RNase I efficiently cleaves after all four bases of single-stranded RNA, compared to RNase A which only Cleaves after C and U residues. RNase I degrades all RNA dinucleotide bonds, leaving behind the 5' hydroxyl group and the 2', 3' cyclic monophosphates. Supplied in a 25,000 U (100 U/µL) tube. RNase I degrades any RNA into a mixture of mono, di, and trinucleotides and does not degrade DNA but binds to it. It has a clear preference for single-stranded RNA over double-stranded RNA, which may allow it to perform well in ribonuclease protection assays. This RNase I was rigorously tested for non-specific contaminating endonuclease, exonuclease and protease activities.

Unit definition:
One unit is the amount of enzyme required to produce 1 µg of acid-soluble material from mouse liver RNA in 30 minutes at 37°C.