Ribonucleases, or RNases, are enzymes that degrade RNA molecules. They are ubiquitous in nature and are found in all living organisms, including bacteria, plants, and animals. RNases can be a major problem in molecular biology, especially in PCR experiments, where RNA contamination can cause false-positive results or inhibit PCR amplification.

To prevent RNA contamination, RNase inhibitors are often added to the PCR reaction mix. These inhibitors can be used to block the activity of RNases, thus preventing RNA degradation. Another approach to prevent RNA contamination is to use RNase-free reagents and equipment, which are specifically treated to eliminate RNases.

There are several types of RNase inhibitors available, such as RNasin and SUPERase-In. These inhibitors can be added to the PCR reaction mix to protect the RNA from degradation.