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RNase A, DNase and protease-free

LO certified Not inactivated at 80°C in 20 min

RNase A is an endoribonuclease that specifically degrades single-stranded RNA at C and U residues.
  
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Thermo Scientific RNase A, DNase and protease-free is an endoribonuclease that specifically degrades single-stranded RNA at C and U residues (see Figure 1 in Supporting Data).

It cleaves the phosphodiester bond between the 5'-ribose of a nucleotide and the phosphate group attached to the 3'-ribose of an adjacent pyrimidine nucleotide. The resulting 2', 3'-cyclic phosphate is hydrolyzed to the corresponding 3'-nucleoside phosphate (see References 1, 2).

Highlights

  • RNase A is free of DNase activity. It is not necessary to heat it before use.

Applications

  • Plasmid and genomic DNA preparation (see References 3, 4)
  • Removal of RNA from recombinant protein preparations
  • Ribonuclease protection assays. Used in conjunction with RNase T1 (see Reference 3)
  • Mapping single-base mutations in DNA or RNA (see References 5, 6)

Notes

Recommended concentration of RNase A is 1 to 100 µg/mL depending on the application. The enzyme is active under a wide range of reaction conditions. At low salt concentrations (0 to 100 mM NaCl), RNase A cleaves single-stranded and double-stranded RNA as well the RNA strand in RNA-DNA hybrids. However, at NaCl concentrations of 0.3 M or higher, RNase A specifically cleaves single-stranded RNA (see Reference 9).

  
Storage Condition-20 C
HazardousNo
Concentration10 mg/mL
Protein concentration is determined by measuring the absorbance at 278 nm using the molar absorption coefficient at 9800 M-1 cm-1 (7).
Definition of Activity Unit
  • One unit of the enzyme causes an increase in absorbance of 1.0 at 260 nm when yeast RNA is hydrolyzed at 37°C and pH 5.0.
  • 50 units are approximately equivalent to 1 Kunitz unit (see Reference 8).
InactivationNot inactivated by heating. Reliably removed by spin column or phenol/chloroform extraction.
InhibitionInhibitors: the most potent inhibitor is a mamalian ribonuclease inhibitor, e.g., <_a20_href3d_22_2f_general-reagents-and-accessories2f_ribolock-rnase-inhibitor2f_3e_ribolock20_rnase20_inhibitor3c_2f_a3e_.20_other20_inhibitors3a_20_uridine20_227_2c_20_327_-cyclic20_vanadate2c_20_527_-diphosphoadenosine20_327_-phosphate20_and20_527_-diphosphoadenosine20_227_-phosphate20_28_229_2c_20_sds2c_20_diethyl20_pyrocarbonate2c_20_4c2a0_m20_guanidinium20_thiocyanate20_plus20_0.1c2a0_m20_227_-mercaptoethanol2c_20_and20_heavy20_metal20_ions.> 
Molecular Weight13.7 kDa monomer
Quality Control
  • The absence of endo-, exodeoxyribonucleases, and proteases confirmed by appropriate quality tests.
  • Functionally tested for RNA digestion in a plasmid DNA purification procedure.
SourceBovine pancreas
Specific Activity>5000 U/mg protein (>100 Kunitz units/mg protein)
Storage BufferThe enzyme is supplied in 50 mM Tris-HCl (pH 7.4) and 50% (v/v) glycerol.
RNase A activity

RNase A activity

RNase A activity

RNase A activity.


References

  1. P. Blackburn, S. Moore, Pancreatic ribonuclease, The Enzymes, V (Boyer, P.D, Ed. 3, Academic Press, New York, the third edition, vol. 15, 1982) pp. 317-433.
  2. R. T. Raines, Ribonuclease A. Chem. Rev. 98, 1045-1065 (1998).
  3. J. Sambrook, D. W. Russell, Molecular Cloning: A Laboratory Manual, the third edition (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2001) pp. 1.31-1.38.
  4. R. C. Sharma et al., A rapid procedure for isolation of RNA-free genomic DNA from mammalian cells. BioTechniques. 14, 176-178 (1993).
  5. R. M. Myers et al., Detection of single base substitutions by ribonuclease cleavage at mismatches in RNA:DNA duplexes. Science. 230, 1242-1246 (1985).
  6. E. Winter et al., A method to detect and characterize point mutations in transcribed genes: Amplification and overexpression of the mutant c-Ki-ras allele in human tumor cells.  Proc. Natl. Acad. Sci. USA 82, 7575-7579 (1985).
  7. M. Sela, C. B. Anfinsen, Some spectrophotometric and polarimetric experiments with ribonuclease. Biochim. Biophys. Acta. 24, 229-235 (1957).
  8. M. A. Kunitz, A spectrophotometric method for the measurement of ribonuclease activity.  J. Biol. Chem. 164, 563-568 (1946).
  9. F. M. Ausubel et al., Current Protocols in Molecular Biology (vol. 1, John Wiley).