RNase A.
Ribonuclease A (RNase A, EC from bovine pancreas is a pyrimidine-specific endoribonuclease that acts on ssRNA (at NaCl conc. >0.3 M). However, if the conc. of RNaseA exceeds 2.2 KunitzU/ml, NaCl conc. <0.1 M and RNA conc. >30 µg/ml, then RNA strand in RNA:DNA duplexes as well as dsRNA will be cleaved. Cleavage occurs between the 3´-phosphate group of a pyrimidine ribonucleotide and the 5´-hydroxyl of the adjacent nucleotide. The reaction generates a 2´:3´ cyclic phosphate which then is hydrolyzed to the corresponding 3´-nucleoside phosphates. RNase A , which works in the absence of cofactors and divalent cations, can be inhibited by placental RNase inhibitor or by vanadyl-ribonucleoside complexes. M.W. approx. 13700. Activity 70- 90 Kunitz U/mg protein.
Unit definition

One unit produces acid soluble oligonucleotides equivalent to DA260 of 1.0 per 30 min at 37°C and pH 7.5.

Reaction conditions
RNase A is active under an extraordinarily wide range of reaction conditions, and it is extremely difficult to inactivate. Use enzyme in excess (1-5 U per ml of overnight bacterial culture (1x109 cells) or mammalian cell suspension (5x107 cells)) to degrade cellular RNA to completion. The optimal working concentration for degradative use is 50-150U/ml.
mapping single-base mutations in DNA or RNA (mismatch analysis); removing unhybridized regions of RNA from RNA:DNA or RNA:RNA hybrids; removal of cellular RNA from DNA preparations; in conujunction with RNaseT1 in RNase protection assay; in conjunction with RNase H for blunt-ending ds cDNA.

Quality control

activity, minimum 70% SDS-PAGE purity.


1. Kunitz, M. (1946) J. Biol. Chem. 164, 563. 2. Laemmli, U.K. (1970) Nature 227, 680.

Catalog #
M11.4 boiled, supplied in storage buffer without glycerol

M12.3 DNase free, supplied in storage buffer with glycerol

Pack size

1000 U

500 U


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