breaking biotin-streptavidin interaction

Gérard Klein Klein at
Wed Sep 27 08:50:43 EST 1995

In article <44a0pa$cl6 at>, doug at (Doug Craig) says:
>Is there a relatively easy way to remove a biotin-labelled peptide from a 
>streptavidin-labelled bead? I would prefer if the streptavidin wasn't 
>killed by the process but if it is it doesn't really matter. It is 
>imparative that the peptide survive and retain the biotin label. The peptide 
>will be sufficiently small that its denaturation isn't a problem.


	If the peptide is small enough for you not to care about
denaturation you should try 8 M guanidine pH 1.5 (use HCl) 10 minutes
at room temperature was enough in my case. Avidin is going to dissociate
into monomer (I don't know how this will act on immobilized avidin)
and will be denaturated. However it will regain its ability to bind
biotin when decreasing the guanidine concentration (3 M seems to
be the upper limit).The dissociation into subunits is said to
be reversible too but I'm affraid that the beads won't resist...

	Be Aware that you can label your peptide with a cleavable analog
of biotin + spacer, for example some spacers contains disulfide bridges
that can be cleaved using DTT or B-mercaptoethanol.

	If you are deeply involved in avidin-biotin chemistry I would
advice you the very good book from Pierce called "Avidin-biotin chemistry,
a handbook".

	Olivier LAURENT

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