|MadSci Network: Biochemistry|
Let me first mention that I'm impressed you're doing a catalase assay in high school. Catalase is a bifunctional enzyme that resides in peroxisomes. It can oxidize substrates such as ethanol by using hydrogen peroxide as an oxidant (the peroxidase reaction), and it also breaks down hydrogen peroxide into water and oxygen gas (the catalase reaction). Hydrogen peroxide destroys DNA and proteins, so eliminating it from the cell is important. Catalases are found in all organisms (including bacteria) that live in aerobic (oxygen-containing) environments. My guess is that liver has a higher level of catalase than the kidneys because it has to handle more detoxification reactions than do the kidneys. As a result, catalase production is greater in the liver in comparison to catalase production in the kidney. In other words, a higher level of a catalase substrate in the cell should lead to higher levels of catalase. I do not know why catalase levels would differ from species to species, other than that chickens and cows have different diets which would require different levels of catalase. Plus, they're distantly related organisms that have distinct physiological differences. If you need more information, please write back. Sarah Earley CU Boulder
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