Ribonuclease A is used to remove RNA from DNA plasmid preparations and protein samples. It is Dnase and protease-free and is used in RNA sequence analysis and protection assays.
Ribonuclease A (RNase A) is an endoribonuclease, that specifically cleaves single-stranded RNA 3′ to pyrimidine residues (cytosine, uracil). Thereby, it generates pyrimidine-3′-phosphate or oligonucleotides with terminal pyrimidine-3′-phosphates. The pH-optimum is in the range of 7.0 – 7.5. RNase A is used for the purification of RNA-free DNA, for the removal of non-hybridized regions of RNA : DNA-hybrides or as a molecular weight marker. The enzyme is inhibited by diethyl pyrocarbonate (DEPC), guanidinium salts (4 M GuaSCN), -mercaptoethanol, heavy metals, vanadyl-ribonucleoside-complexes, RNase-inhibitor from human placenta and competitively by DNA, respectively. Regarding the latter, the effect of denatured DNA is higher than by native nucleic acids. Nevertheless, RNase A is very active under very different conditions and difficult to inactivate. At low salt-concentrations (up to 100 mM NaCl), RNase A cleaves single- and double-stranded RNA and RNA in RNA : DNA- hybrides. Under high salt concentrations (>300 mM NaCl) single-stranded RNA is cleaved only. To remove the enzyme from samples, it has to be digested by proteinase K (frequently, SDS at a final concentration of 0.6 % is added) and several phenol extractions are required. (Applications: Enzymatic manipulation of DNA and RNA: ref. 1 Suppl. 8 p. 3.13.1; minipreps of plasmid-DNA: ref. 1 Suppl. 24 p. 1.6.6;
1 g, 100 mg, 500 mg