Preservation of cyt. c solns

jopa at ac.dal.ca jopa at ac.dal.ca
Tue May 25 05:16:13 EST 1993


In article <1tbqrk$f4r at zippy.Telcom.Arizona.EDU>, droberts at joplin.biosci.arizona.edu (Doug Roberts) writes:
> 
> 	This reminds me of a discussion/argument that I had with a labmate
> recently. She argued that the reason for always keeping proteins in the cold
> was to prevent denaturation. I believe that it must be for some other reason,
> perhaps to prevent microorganism growth, or to slow down the activity of
> proteases that may be present in the sample. It seems to me that at room     
> temperature, most proteins will be stable against denaturation. (Most of the
> melting curves I've seen are quite flat around this temp.) The other point
> is that we grow up our yeast at 36C and their proteins seem to work just
> fine

I suspect that there is a case for both.  However, the denaturation
which may be occurring at room temp.  may not be a simple folding-
unfolding denaturation, it could be a slow chemical process, ie. 
some oxidation or auto-proteolytic or, as you mentioned, the
presence of additional proteinases.  I would say it a question
of time...proteins which are ok in yeast at 36C may not be okay
in pure or semipure solution at 21C, since the environment is
so different.  

Certainly the presence of microorganisms is a definite concern, I have
seen solutions go bad and it is definitely because something is growing
in it.

Jonathan Parrish
Department of Biochemistry
Dalhousie University
Halifax, N.S., Canada



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