Peroxisomes, discovered by British cytologist and biochemist Christian de Duve, are surrounded by a single membrane and are the most common type of microbody (an organelle containing enzymes) in cells. They are especially prominent in algae, the photosynthetic cells of plants, and both mammalian kidney and liver cells. Peroxisomes contain detoxifying enzymes and produce catalase, which helps to break down hydrogen peroxide into hydrogen and water.