RNase Inhibitor is a recombinant mammalian RNase inhibitor that is purified by a combination of ion exchange and hydrophobic interaction chromatography to yield a physical purity >90%. The protein is capable of inhibiting eukaryotic RNases (e.g., RNase A and RNase B) similar to human placental RNase inhibitor. RNase Inhibitor forms a stable complex with RNases, inactivating the RNase. This complex is stable at temperatures up to 70°C for at least 15 minutes. RNase Inhibitor has been tested in RT-PCR and is compatible with enzymes such as AMV, M-MLV.