blocking in northern blots

[Doug Craig]

I am trying to stick target DNA to a piece of nitrocellulose, bind 
biotinylated probe to it and detect with streptavidin-alkaline 
phosphatase conjugate. I get a high background. Does anyone out there 
have a favorite blocking method that works well? So far I have been 
blocking with herring DNA and BSA. I am using a very high sensitivity 
alkaline phosphatase assay which I have developed and require very 
effective blocking.

I am not limited to nitrocellulose. I would also like to hear of any good 
methods people out there have for other membranes.

Thanks,

Doug


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Doug Craig                           | 
Chemistry                            |  In theory there is no difference 
University of Alberta                |  between theory and practice,
Edmonton, AB T6G 2G2                 |  but in practice there is.
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doug at hobbes.chem.ualberta.ca         |       
doug.craig at ualberta.ca               |
http://hobbes.chem.ualberta.ca/~doug |
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