PEG : to autoclave or not to autoclave, that is the ques

[Bernard Murray]

In article <1994Feb15.085613.7863 at abo.fi>, JANIEMI at FINABO.ABO.FI (Jarmo Niemi) writes:
> In <2jou5u$lpk at mule.fhcrc.org> Tim writes:
> 
> > Is there a reason why protocols for PEG precipitation of phage specify
> > that it should be filter sterilized? 
> > What's supposed to happen if you autoclave it?????
> 
> In my experience, solutions with PEG and NaCl, even when autoclaved
> separately, turn yellow after some time. Filtered PEG-NaCl solutions
> seem to do this much more slowly. What happens, I don't know, and DNA
> prepared with yellow PEG-NaCl can be sequenced, IMH (In my hands...).
> 
>Jarmo Niemi   Biochemistry, University of Turku, Finland, janiemi at finabo.abo.fi

Also, we routinely use autoclaved PEG for cell fusions in monoclonal antibody
production.  Yes, it is slightly yellow but it still does the job.  In fact
I doubt if you could actually filter sterilise such high MW PEGs.

Bernard Murray, Ph.D.
bernard at elsie.nci.nih.gov   (National Cancer Institute, NIH, Bethesda MD, USA)