THAT the catalytic decomposition of hydrogen peroxide by catalase requires the presence of molecular oxygen was demonstrated by a number of manometric experiments previously described 1.

Catalase is a ubiquitous enzyme found in nearly all living organisms, from bacteria to humans. Its primary function is to decompose hydrogen peroxide, a byproduct of metabolic reactions, into water ...

Thousands of different chemical reactions must happen inside ... In this example, the enzyme catalase acts on the substrate hydrogen peroxide to make the products water and oxygen.

Enzymes speed up reactions - they make things happen quicker. In our bodies hydrogen peroxide is broken down by the enzyme called catalase. Sorry I don't do liver - I just I don't like it.