non radi detection/ blocking?

Ted Davis davis at
Tue May 10 14:55:18 EST 1994

>I'm trying out a non radioactive detection kit
>from S&S involving biotin labeled probes and
>strepaviton- alk phos -chemilum detection.  During
>the incubation and right before it (the strepavit step)
>the kit calls for some "blocking reagent" which of course
>does not list any ingredients and is expensive.  So I
>am asking if anyone has a home-made recipe for a
>blocking reagent that is inexpensive, since we are
>a small acad. lab. on a tight budget.
>rocket1 at


First you should ask them if they will supply the recipe, it certainly
would be good PR for them.  If this fails, you could try the blocking
solution we use in our nonradioactive detection system (sorry its not more

Blocking Solution

5% SDS
20 mM sodium phosphate, pH 7.2

We recommend that the streptavidin and biotin-alk phos be diluted in this
buffer for their incubations.  The washes between layers are performed in
this solution diluted 1:10.  If you need more details, E-mail me and I'll
send you the manual (gratis, of course :))


Ted Davis
New England Biolabs
(508) 927-5054 X334
davis at

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