Peroxidase

Peroxidases are a large family of enzymes that generally follow the mechanism below.

The figure above shows the two one electron oxidations of the reducing substrate with hydrogen peroxide as the oxidizing substrate.

These enzymes are found repeatedly throughout nature and are used to perform a diverse set of tasks, ranging from the myeloperoxidase found in a subtype of white bloodcells, to lactoperoxidase found in milk.