Re: osmium tetroxide-immunoreactivity

From:"J. A. Kiernan" <>

On Mon, 9 Jul 2001, Rudolf Schicho wrote:

> I've just read Dr. Kiernans answer to Debra Dunlap about osmium
> tetroxide for autofluorescence. Can osmium tetroxide treatment damage
> the immunoreactivity of your target protein?

Yes, that's a possibility. Traditional fixation in OsO4
(or post-osmication for that matter) greatly reduces affinity
for anionic dyes, presumably by bringing about oxidative
deamination of lysine side-chains. I don't think this
happens on a large scale with the milder treatment applied
to paraffin sections, but it would be sensible to compare
the appearances in sections that have & have not received
the OsO4 treatment and washing.
John A. Kiernan
Department of Anatomy & Cell Biology
The University of Western Ontario
London,  Canada   N6A 5C1

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