Protein free blocking agent

Fred dynamin at
Wed Nov 10 22:58:00 EST 1999

Funny.  We use NC and PVDF both.  Exclusively use chemi.  Never really
noted a problem, having used it for about 6 yrs.  Still using it now. 
No other changes to standard blot protocols.  An advantage of the PVP40
is you can amido black (or coomassie) stain after chemi, rather than
before.  We find this very useful (still works after milk blocking, but
not so well).

whats' "A/B"?  We switched to PVP40 from skim milk.


Stephen Dahl wrote:
> 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?
> Regards,
> Steve Dahl
> stebby at

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