Protein free blocking agent

Stephen Dahl stayve-and-irayne at
Mon Nov 1 00:44:10 EST 1999

Fred <dynamin at> wrote in message
news:38195DF5.8A326B2 at
> We use PVP-40 (very cheap from Sigma) to block NC or PVDF for western
> blots.  Works extremely well.  Never tried it for hybridisations, but
> should work equally well (I would guess).
> see: Haycock, J.W. (1993) Polyvinylpyrrolidone as a blocking agent in
> immunochemical studies.  Anal.Biochem.  208, 397-399.

Interesting.  I saw this paper, tried it, and found it to work extremely not
so well.  Did you A/B it with gelatin, BSA, milk, etc.?  I'd be interested
in whether you altered the protocol at all.  In my hands, coomassie blue
would have given the same results.  Are you doing chemi or colorimetric?

Steve Dahl
stebby at

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