We have repeatedly observed that aqueous peroxide solutions do not quench
thoroughly when large amounts of endogenous peroxidase are present.  We use
the following solution, which works much better for us:

Methanol ................ 300 ml
Hydrogen Peroxide ... 5.0 ml
HCl ........................  0.6 ml

Usual time is 20 minutes.

Paul M.

> ----------
> From: 	histonet-bounces@lists.utsouthwestern.edu on behalf of Pablo
> Sánchez Quinteiro
> Sent: 	Friday, July 22, 2005 8:11 AM
> To: 	histonet@lists.utsouthwestern.edu
> Subject: 	[Histonet] Endogenous peroxidase blocking
> 
> Dear Histonetters,
> 
> I ask for your help. I am doing an immunohistochemical procedure in really
> bloddy specimens. The endogenous peroxidase blocking solution is 3% v/v
> hydrogen peroxyde in distilled water for 15 minutes.
> 
> I am afraid that this blocking is not enough. How can I be sure that I
> have
> totally removed the endogenous activity? Are there stronger treatments
> than
> mine?
> 
> Should the endogenous peroxidase staining appear only in red cells and
> granulocites or could it also produce a background staining in the whole
> tissue?
> 
> Best regards
> 
> Pablo Sanchez
> 
> 
> 
> 
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> 

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