Preservation of cyt. c solns

davidw at davidw at
Thu May 6 18:16:37 EST 1993

I am currently studying the redox potential of cytochrome c in aqueous
solution.  As the stuff is pretty expensive $100/.1g, I am trying to reuse
my solutions.  The conditions are:  1mM Horse heart cytochrome c in 0.1M
KPhos buffer at pH=6.  The buffer has been filtered through .22um filter
to eliminate bacteria and is stored in a sterile bottle.  As I work in a
chem lab, we do not have access to alot of sterile glassware, so I do the
best I can by rinsing the glassware with EtOH followed by several rinses with
the sterile buffer to remove the EtOH.  My current storage procedure is to
put the solution (aprox 1mL) in a 10mL screw-cap test tube and quick
freeze it in liquid N2, it is then stored in a -10C freezer.  I thaw the
protein by placing the tube in a beaker of cold tap water.  My questions
are the following:

1.  Is bacteria really a threat to the protein?
2.  If not bacteria, what will damage the protein?
3.  What is the best way to store the solution for short periods of time
(a few days at a time)?

David Weis                              davidw at
Chemistry Department                    DAVIDW at EARLHAM
Earlham College

    "Every scientist is half B. F. Skinner and half P. T. Barnum."
                           --The Simpsons
        "You can't argue with Hess's Law, that's why it's a law."
                  --an anonymous chemistry professor

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