I use 0.3% in PBS for 30 minutes. It blocks peroxidase just fine without
being as damaging to tissues (in my opinion). You can also use a higher
H2O2 concentration ie 3% for only 5 minutes if time is an issue. 

Hope this helps,

Marcia

At 10:41 PM 08/27/2000 -0700, Marek Malecki wrote:
>Would anyone have a suggestion for blocking endogenous peroxidases before 
>HRP labeling better than methanol/H2O2 or NaN3?
>
>M. Malecki, M.D., Ph.D.
>Director and Principal Investigator
>
>Molecular Imaging Laboratories
>University of California at San Diego
>address: 1500 Suite Bonner Hall, 9500 Gilman Drive, La Jolla, CA 92093-0368
>phone: 8588223373
>fax: 8588223715
>pager: 8586161420
>e.mail: mmm@ucsd.edu
>e.pager: 1620024619@alphapage.airtouch.com
>www site: http://mil.ucsd.edu/
>ftp site: mil1.ucsd.edu
>
>
>
>
>
>
>
>
Marcia Bentz
Lab Specialist Sr
University of Virginia
Medicine/Nephrology
mb7x@virginia.edu
804-982-1069