peroxisome A small organelle (a type of microbody) that is bounded by a single membrane and found in plant and animal cells. It contains enzymes that are involved in oxidation processes, some of which generate the highly toxic compound hydrogen peroxide (H₂O₂). Hence, peroxisomes are equipped with catalase, an enzyme that breaks down H₂O₂ into water and oxygen. Peroxisomes are the main site of fatty-acid oxidation in plant cells and also play a significant role in this regard in animal cells. They are responsible for neutralizing toxins absorbed from the blood, especially in cells of the liver parenchyma and proximal convoluted tubule of the kidney. In plants, peroxisomes detoxify certain by-products of photosynthesis and oxidize glycolate (produced by photorespiration) to glyoxylate, which can then be salvaged by a series of reactions involving mitochondria and chloroplasts as well as peroxisomes.

peroxisome A round or oval, membrane-bound organelle, 0.3–1.5 μm in diameter, found in numbers in most eukaryotic cells. Typically, it has a finely granular, relatively dense internal structure, and contains numerous enzymes (particularly catalase) associated with the production and degradation of peroxides. See also GLYOXYSOME.

peroxisome A round or oval, membrane-bound organelle, 0.3–1.5 μm in diameter, that is found in numbers in most eukaryotic cells. Typically, it has a finely granular, relatively dense internal structure, and contains numerous enzymes associated with the production and degradation of peroxides, in particular the enzyme catalase. See also GLYOXYSOME.