MadSci Network: Medicine |
Dear Bob,
Hydrogen peroxide (H2O2) is highly toxic to cells because it is an
unstable, and therefore highly reactive compound. Our immune system uses
the toxicity of hydrogen peroxide to kill off bacterial invaders. The
release of hydrogen peroxide in our bodies not only kills bacterial cells,
but kills our body's cells too. To protect against damage by our own
immune system, our cells produce an enzyme called catalase. Catalase
breaks down the toxic hydrogen peroxide into harmless water and oxygen
gas. An excellent explanation for how
catalase works can be found in a MAD Scientist essay by Lynn Bry.
Unfortunately for us, some bacteria can also produce catalase.
This bacterial catalase does well in protecting the bacteria against the
hydrogen peroxide our immune systems throws at them. (For a list of some
infectious bacteria which produce catalase, see this link to a page at Da
rtmouth College.)
We do have one more advantage in the battle against the catalase-producing
bacteria. We can buy mass-produced hydrogen peroxide, and pour it on our
infected skin. The large amount of hydrogen peroxide we add topically is
far more than the bacteria can neutralize with their catalase. We simply
over-whelm them with the volume of hydrogen peroxide we use.
It's important to be careful with hydrogen peroxide, however. Remember,
it not only kills bacteria by overwhelming its catalase, it also kills
our own cells by overwhelming our own catalase. Please read the
directions carefully or consult a physician before using hydrogen peroxide.
Thank you for your question!
John
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