Ribonuclease Inhibitors

RNA analysis and quantification require completely intact, nondegraded RNA samples to produce optimal results. Although nonenzymatic hydrolysis of phosphodiester bonds is favored by high temperature or pH and the presence of divalent cations (Mg²⁺ , Mn²⁺ ), an RNA sample is most likely to be rapidly degraded by a contaminating ribonuclease (RNase). RNases are difficult to completely remove or inactivate during RNA isolation procedures, and they may be introduced into the sample inadvertently during its handling. There are several possible sources for RNases in the laboratory. RNases are ubiquitous in the environment, and are found on pollen, dust, and fingerpaint grease. Routine lab procedures, such as ribonuclease protection assays or degrading RNA in plasmid preparations, introduce highly purified, concentrated RNases. RNase may be in the powdered reagents used to make the stock solutions or in the tips and tubes used for handling the RNA.