RNAse for phage preps

[WWW-Brower auf bigapple/1.Stock]

John and Juqun,
thank you for the answers. I must say that I am quite sure that I 
protect my DNA from myself and I prepared the RNAse more or less the way 
you suggest.
I am also sure that it is indeed the RNAse because I ran a gel with 
samples that were treated with everything I was using but one component 
and only the lane without RNAse looked o.k. 

My impression is that it is not a DNAse problem but rather something 
that binds to the DNA in the gel and inhibits formation of bands. I had 
the same experience that you mentioned, John, with crude RNAse years ago 
but could not remember the exact source. If my explanation for the 
strange behavior is correct then it is possible that this phenomenon 
changes from batch to batch. It would therefore be very useful for 
companies to just just screen for it and market an in-between quality 
type RNAse for a reasonable price or for netters to publish batch 
numbers.

Are there other people who can confirm my observation or have other 
ideas to explan it?

Rainer Blaesius
Inst. f. Biochemie
Fahrstr.17
D-91054 Erlangen