Novel form of Superoxide

BRIAN LEE brian.lee at woodlawn.com
Tue Feb 14 00:24:00 EST 1995


Marius Brouwer noted:
|MB> the activity of this protein cannot be inhibited by cyanide, hydrogen  |
|MB> peroxide or diethyldithiocarbamate, which would qualify this protein as|
|MB> a MnSOD which seems very unlikely. Has anybody ever seen a CuZnSOD that|
+---------------------------------------------------------------------------+

MnSOD is generally associated with mitochondria, at least in
upper vertebrates.  I think it may be cytosolic in bacteria.  I
don't know about crustaceans.  My next guesses would be Co and
V, both in the transition metal area capable of various redox
states.  Examples: Co in vitamin B12 and V as the oxygen carrier
in tunicate blood.

If you get enough of the protein, you can try a quick nitric
acid digestion and microelectroanalysis. If you had a lot, you
could run an ICP-ES elemental scan for perhaps a dozen elements
at once.  A more tedious route would be to run x-ray
microanalysis on some adsorbed and fixed onto a surface.

Now that I think about it, I recall someone trying to substitute
different metals into an SOD just to see what worked.  Hey, I
know where it is.....<looking through my PhD thesis>  Try this
reference:
D Cocco, L Calabrese, A Rigg, et al- "Preparation of selectively
metal-free and metal substituted derviatives by reaction of
copper-zinc superoxide dismutase with diethyldithiocarbamate."
Biochem J 199:(3) 678-680 1981.

I also wrote that "MnSOD is destroyed by chloroform:ethanol;
CuZnSOD is not."  This references RA Weisiger & I Fridovich-
"Mitochondrial superoxide disumutase" J Biol Chem 248:(13)
4793-4796 1973.

Gee, the thesis is still a gem even after copyrighting 10 years
ago and that I even remembered that :)   Let me know what you
find.
---
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