Strepavidin Beads

Paul N Hengen pnh at
Wed Dec 14 17:35:54 EST 1994

 In article <3ckjj2$p78 at>
 karl at (Karl Voss) writes:

| Does anyone know of a good supplier of the magnetic strepavidin beads
| for cleanup of biotin labeled DNA.  We purchased our last bit from 
| DYNAL but I figured there might be a cheaper supplier if we bought a 
| large quantity at once.  


Promega sells a cheaper version. The paramagnetic particles are supplied by
Advanced Magnetics, Inc.  1-800-343-1346; however, the specs from Advanced
Magnetics do not apply for some reason. I think the beads are further diluted
after Promega gets them. Also, these beads are a different size than the Dynal
Dynabeads M-280 Streptavidin so don't be fooled into thinking they're all the
same, ie. different size = different binding capacity. In fact, the Promega
blobules are quite amorphous in shape, which may allow for particle
disintegration through abrasive friction created when pipetted. I have evidence
that the Promega beads fall apart during my experiments. If all you want to do
is remove the biotin or biotin-containing DNA from solution, these will cost
less than Dynal beads. However, they are not of the same quality.

* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at |*
* Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |*
* Frederick Cancer Research and Development Center|     FAX: (301) 846-5598  |*
* Frederick, Maryland 21702-1201 USA              /--------------------------/*
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