CATALYST
How Does Catalase Work?
1) Each of the four subunits of catalase has a cavity with an iron containing heme group at its center and a histidine protruding into the cavity.
2) Hydrogen peroxide (substrate) enters the cavity.
4) The hydrogen and the remaining oxygen are attracted to the histidine (amino acid).
3) One of the oxygen atoms binds to the iron in the heme group.
5) The bond between the two oxygen atoms in the hydrogen peroxide molecule is severed. As a result water is created when the remaining O-H component attracts the hydrogen atom attached to the histidine.
7) Oxygen gas and water are created.
6) Another hydrogen peroxide molecule enters the cavity; the oxygen attached to the iron in the heme group is pulled away
The substrate, a hydrogen peroxide molecule, binds to a small portion of the enzyme known as the active site. The hydrogen peroxide is attracted to the active site, as the substrate comes in close proximity of catalase the functional groups of the enzyme are attracted to the hydrogen peroxide molecule. Interactions and bonding between the enzyme and the substrate force catalase to change its physical shape to better accommodate the hydrogen peroxide molecule. While the hydrogen peroxide molecule is in the active site the hydrogen bonds/ covalent bonds between the hydrogen peroxide molecule are broken and the bonds needed to create water and oxygen are formed.
