RNAse stability

Fri Aug 19 09:48:38 EST 1994

Robert Slany writes:

> Does anyone of you have experience with the stability of RNAses? O.K. I know
> that there is the saying that RNAse A is not inactivated by autoclaving.

My understanding is that RNAseA denatures with heating like any other 
protein.  But, unlike most proteins, it readily renatures.  So the
activity comes back.  If there's just a trace, it may not come back. 
If there's a big slug of RNAse A present, then it'll renature so fast
you'd think nothing ever happened to it.

> But on my shelf at roomtemperature the Tris/EDTA buffers supplemented with
> RNAseA decay within 2 months (Only residual RNAse activity left.)

I've seen 20 mg/ml concentrated RNAse solutions precipitate on storage at 4 C.
More dilute solutions seem to last forever in my fridge.

> Did anyone of you really try once to autoclave the RNAse?

I've successfully cleaned up contaminated reagents by autoclaving.  As pointed
out by others, the contamination wasn't necessarily RNAseA.  But 
environmentally introduced RNAses often tend to be just as tough as RNAse A.
These proteins are secreted into a hostile environment and they are designed
to survive there.

> This would be really interesting since one could spare all the precautions
> for RNA preparations if RNAse could be inactivated by autoclaving.

I can't recommend sparing *any* precautions when it comes to handling
RNA.  The ratio [potential for grief]/[time spent on precautions]
is very high.  :-O

Steve Hardies, Dept. Biochem., Univ. of Texas HSC at San Antonio
Hardies at thorin.uthscsa.edu

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