I'm following this question with interest, not sure if there's anything specific for this. People have usually demonstrated mitochondrial H2O2 through combined use of complex inhibitors, such as rotenone, then using catalase or PEG-Catalase. Specific MnSOD knockdown in comparison to Cu/Zn- and EC-SOD knockdown may also help. Mitochondrial H2O2 can be measured using mitoPeroxy yellow. Not sure if mitochondrial peroxide can be specifically scavenged though. 

Glad to initiate an interest thread, DaviD.

I was aware that mitochondrial superoxide anions and H2O2 can be revealed through some specific fluorescent probes, however I need to find membrane-permeable compounds that specifically react and scavenge mitochondrial hydrogen peroxide, so I may be able to establish whether my cellular response is based on enhanced mitochondrial H2O2 production.

Best regards

Stefano

I'm waiting with interest to hear from others.

You could overexpress a mitochondrially targeted form of catalase.

Regards

Giuseppe

Thanks, Giuseppe. The idea of overexpressing a H2O2-targeting enzyme already crossed my mind. My choice would be glutathione peroxidase, rather than CAT due to the lower Km, however I'd prefer to use a chemical compound (simpler and less time-consuming procedure).

Thanks again

Stefano

I have srtudied catalase presence in rat heart< brain, spinal cord and liver mitochondria. Catalase is present in rat liver mitochondria only. The results are published in a paper I have attached to this notice. Data on the rat heart were not published. What is interesting, that spinal cord homogenate does not contain SOD1, but brain does. In SOD1-mutant rats SOD1 was present in both tissues, My paper in neurobiology of Disease 2011, Vol. 44, 53-62.

Hi, Alexander. I knew that most cells lack mitochondrial catalase. That was another reason that led to the possible choice of overexpressing glutathione peroxidase. However, as I already said, I'd prefer to find a specific chemical compound through which mitochondrial H2O2 could be trapped or scavenged. Thanks for Your precious contribution.

Stefano

You may wish to contact Patrick Pagano or Sergey Dikalov who have a long standing background in redox pharmacology. Patrick actually developed the gp91ds-tat peptide inhibitor of Nox2. One of those may be able to assist. Ajay Shah (Kings College London), Rhian Touyz (Glasgow)  and Kathy Griendling are others you could also ask. 

I'll try. David. Thank You very much, again.

Stefano 

If testing isolated mitochondria, pyruvate (enters mitochondria freely) may be a good scavenger of hydrogen peroxide because it is decarboxylated non enzymic by hydrogen peroxide. See specific article in:

http://www.ncbi.nlm.nih.gov/pubmed/9214579

Thanks to You too, Christos.

Unfortunately, I have to keep my cells alive, so mitochondria isolation cannot be carried out.

Regards

Stefano