Biology Forums - Study Force

Hello everyone!

We are about to begin this lab concerning catalase breaking down hydrogen peroxide.
I just wanted to do some extra research before we begin, and ask what are the properties of catalase, how does it break down hydrogen peroxide, and what are any other information about catalase that anyone may know?

Thanks so much in advance everyone!

Catalase enzyme is found virtually everywhere in your body. You know when you put hydrogen peroxide as a disinfectant on a cut and you see the a white film forms, thats the catalase enzymes in your blood converting the hydrogen peroxide into oxygen and water. Catalases convert 2H2O2 into 2H2O + O2 molecules. They also have a very high turnover ratio compared to any other enzyme found in the body; one molecule of catalase can convert millions of molecules of hydrogen peroxide to water and oxygen per second. Also, this enzyme is typically located in the cellular organelle called the peroxisome.

Thanks duddy, does anyone else have any more information? It would be appreciated

Catalase is found nearly all living organisms. The enzyme catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a tetramer of four polypeptide chains, each over 500 amino acids long. It contains four porphyrin heme (iron) groups that allow the enzyme to react with the hydrogen peroxide. This is similar to hemoglobin because hemoglobin also has heme groups! The optimum pH for human catalase is approximately 7, but don't go beyong 6.8 and 7.5! Also, human catalase works at an optimum temperature of 37°C.

It's role in cells:

Because our cells, in particular immune system cells, produce a lot of hydrogen peroxide to kill pathogens, we have this enzyme to prevent damage. So this enzyme quickly converts hydrogen peroxide into other, less dangerous substances which I just mention above. As a result, catalase is frequently used by cells to rapidly catalyze the decomposition of hydrogen peroxide into less reactive gaseous oxygen and water molecules.

Catalase is usually located in a cellular organelle called the peroxisome. If you ever spray hydrogen peroxide on your gums, they will turn white temporarily and like what Duddy mention, the white is the oxygen that is produced!

I hope this clears it up :D.

Thanks bio_man
just wondering would you happen to have some sort of articles or sources of information for just information about catalase so that I could cite some of them in my lab? Legitimate websites, articles, anything that I could also use as explanations for the results of my lab would be appreciated.

Absolutely.

Chelikani P, Fita I, Loewen PC (January 2004). "Diversity of structures and properties among catalases". Cell. Mol. Life Sci. 61 (2): 192–208.

I will have to download this for you because it costs money :-\. I have an account though.

Boon EM, Downs A, Marcey D. "Catalase: H2O2: H2O2 Oxidoreductase". Catalase Structural Tutorial Text. Retrieved 2007-02-11.

http://biology.kenyon.edu/BMB/Chime/catalase/frames/cattx.htm (http://biology.kenyon.edu/BMB/Chime/catalase/frames/cattx.htm)   Really Good.

Catalase in vitro

http://tiny.cc/a9fvd (http://tiny.cc/a9fvd)

I will have to download this for you because it costs money :-\. I have an account though.

Really Cool article:  http://www.heveliusforum.org/Artykuly/Biomimetics.pdf (http://www.heveliusforum.org/Artykuly/Biomimetics.pdf)

Tell me if you need them downloaded...

No no, that's absolutely fine! You have helped enough already. Thank you so much!

You're welcome.

Thanks for the help bio_man  :)
One more question,
for the lab I need to investigate the effects of one variable (ie. pH, temperature) on catalase.
Since pH has such a drastic affect on catalse, do you have tips on which acid I should use and what the concentration of that acid should be to get a good result of affected catalase without completely denaturing all of them?

Wait, why use acid? Why not go with temperature, it's so much easier! Reply back for more details ;D!

Anyways, use a strong acid like HCl and dilute it to what your protocol desires.

Argh, sorry bio_man, my teacher ended up assigning us the variable because kids just decided to not do research.
Now I'm stuck with catalase inhibitors as the variable. Do you have any suggestions for common inhibitors that are safe? I found out that nitro derivatives tend to inhibit catalse but I'm sure there are more common inhibitors out there.

Thanks bio_man.

Hey rainbows246,

The only chemical I can think of is ammonium hydroxide (aqueous ammonia) and it is readily available ;).

Ammonium hydroxide, although it doesn't exist as an isolatable chemical compound, is a name sometimes given to an aqueous solution of ammonia. Aqueous solutions of ammonia are also commonly referred to as aqua ammonia. In aqueous solution, ammonia deprotonates some small fraction of the water to give ammonium and hydroxide ions according to the following equilibrium:

NH3 + H2O --> NH4+ + OH-

With a base ionization constant (Kb) of 1.8×10-5, in a 1M ammonia solution about 0.42% of the ammonia will gain protons to become ammonium ions (equivalent to a pH of 11.63).

Aqueous ammonium hydroxide can also dissolve various metal oxides and hydroxides, such as copper(II) hydroxide to form ammine complexes. In such cases, the active agent is the ammonia, not the hydroxide salt. Solutions of ammonium hydroxide can also dissolve reactive metals such as aluminum and zinc, with the liberation of hydrogen gas. When ammonium hydroxide is mixed with dilute hydrogen peroxide in the presence of a metal ion, such as Cu2+, the peroxide will undergo rapid decomposition.

Check out this article:

http://www.ncbi.nlm.nih.gov/pubmed/17214191 (http://www.ncbi.nlm.nih.gov/pubmed/17214191)

Catalase is inhibited by a number of small molecules, including ammonia, HCN, and by azide. I am unaware of any inhibitor that is specific solely for catalase. There is a very large amount of literature on this enzyme.