Biotin contamination of BSA

[WS]

Dear Experts,

I noticed that "ordinary" BSA is unsuitable for blocking westerns when
streptavidin HRP is used, as it causes high background by its biotin
content. Where does the Biotin contamination come from and how may I
get rid of it (except buying biotin free BSA)? Is it covalently
linked?

Best regards,

Wo

[Dr Engelbert Buxbaum]

Try fish skin (teleost) gelatin instead, or polyvinylpyrollidone (PVP). If
you blot on PVDF membranes, you do not need to block at all. Air-dry the
membrane completely, then all solutions can interact only with
surface-bound proteins, but not with the very hydrophobic membrane -> no
background binding.

[ruchi jain]

Do the blocking with either gelatin or skimmed milk. We have been using
skimmed milk and I would say its a cheap and a very good way of blocking in
westerns.
Best
Ruchi

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--
Ruchi Jain, Ph.D.
Postdoc Associate
Internal Medicine-Infectious Diseases
Yale University
ruchi...@yale.edu
203-737-1197