Prot. A Sepharose-Regeneration

Dr E. Buxbaum EB15 at le.ac.uk
Fri Aug 1 11:06:18 EST 1997


espinoza at cgl.ucsf.edu (Hernan Espinoza) wrote:

>>There is a different option. Calbiochem sells dead S. aureus bacteria 
>>with Protein A on their surface ("Pansorbin").

>	I have thought about this, but I have always been concerned about
>background.  


This depends on your detection method. Obviously you cant use them for 
Coomassie staining of the gels. However, if your material is specifically 
labeled, this label will not be present in the bacteria and therefore the 
bacteria do not contribute to the background. I have been using Pansorbin 
for a fusion assay, where 2 vesikel populations (one containing 125-I-antigen, 
the other antibody) fuse. The amount of fusion is then measured by detergent 
lysis of the vesikels (in the presence of excess cold antigen, of course) 
and binding the hot immunocomplexes to Pansorbin. Background about 45 cpm, 
max signal 2000-3000 cpm. The stability of the antigen-antibody and 
antibody-Protein A complexes allows the use of fairly rigorous washing 
conditions. 




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