Catalysts: Catalase

As you know, catalysts are components in a chemical reaction that speed up a process. The number of types of catalysts is truly amazing, but one that may be of some interest is an enzyme known as Catalase. Catalase is one of the most potent catalysts known. It is found in high concentrations in a “compartment” located in cells known as the peroxisome. Nearly all aerobic cells of plants and animals contain catalase. It aids in the process of protecting cells from the toxic effects of hydrogen peroxide by speeding up the decomposition of H₂O₂ into water and oxygen without producing free radicals.

Even though all the minute details of the process have not been specifically determined, the overall reaction is as follows:

A more detailed idea of the way catalase works has been proposed. The reaction is similar to the way cytochrome c peroxidase works. The process is thought to happen in two steps as follows:

Here Fe-E represents the iron center of the heme attached to the rest of the enzyme (E).” Along with breaking down hydrogen peroxide, catalase also uses H₂O₂ to oxidize toxins, which include phenol, formic acid, formaldehyde and alcohol.

Catalase has been one of the first enzymes to be purified to homogeneity. Many studies have been undertaken to try to figure out how exactly this enzyme works and its structure. It has been discovered that it is among the most efficient enzymes known, with catalytic rates approaching nearly 200,000 events/second/subunit. The structure of the catalase enzyme from many different species has been studied, and it has been determined that all catalases share the same general structure, though some differ in the number and identity of domains.