- RNase A.
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- Description
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- Ribonuclease A (RNase A, EC 3.1.27.5) 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.
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- Unit definition
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One unit produces acid soluble oligonucleotides equivalent to DA260
of 1.0 per 30 min at 37°C and pH 7.5.
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- Reaction conditions
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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.
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- Applications
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- 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.
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Quality control
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activity, minimum 70% SDS-PAGE purity.
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References
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1. Kunitz, M. (1946) J. Biol. Chem. 164, 563. 2. Laemmli, U.K. (1970)
Nature 227, 680.
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- Catalog #
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- M11.4 boiled, supplied in storage buffer
without glycerol
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M12.3 DNase free, supplied
in storage buffer with glycerol
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Pack size
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1000 U
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500 U
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