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An intracellular organelle found in all eukaryotes except the archezoa (original lifeforms). In electron micrographs, peroxisomes appear round with a diameter of 0.1–1.0 micrometer, although there is evidence that in some mammalian tissues peroxisomes form an extensive reticulum (network). They contain more than 50 characterized enzymes and perform many biochemical functions, including detoxification. See Cell organization, Enzyme

Peroxisomes are important for lipid metabolism. In humans, the β-oxidation of fatty acids greater than 18 carbons in length occurs in peroxisomes. In yeast, all fatty acid β-oxidation occurs in peroxisomes. Peroxisomes contain the first two enzymes required for the synthesis of plasmalogens. Peroxisomes also play important roles in cholesterol and bile acid synthesis, purine and polyamine catabolism, and prostaglandin metabolism. In plants, peroxisomes are required for photorespiration. See Lipid metabolism, Photorespiration

A number of recessively inherited peroxisomal disorders have been described and grouped into three categories. Group I is the most severe and is characterized by a general loss of peroxisomal function. Many of the enzymes normally localized to the peroxisome are instead found in the cytosol. Among the diseases found in group I are Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease. Patients with these disorders usually die within the first years after birth and exhibit neurological and hepatic (liver) dysfunction, along with craniofacial dysmorphism (malformation of the cranium and the face). Groups II and III peroxisomal disorders are characterized by a loss of peroxisomal function less severe than in group I.


(cell and molecular biology)
Any of a subclass of microbodies that contain at least four enzymes involved in the metabolism of hydrogen peroxide.
References in periodicals archive ?
Cusson Osthol Alcoholic fatty liver Peroxisome proliferator-activated receptor [alpha] MK886
is a partial agonist/antagonist of the peroxisome proliferator-activated receptor (PPAR)--gamma.
The new agent mimics a compound called peroxisome proliferator activated receptor-delta, or PPAR-delta.
market in March 2000 because of excess hepatotoxicity, there has been lingering concern that the problem could be a class effect common to all thiazolidinedione (TZD) agents or to other drugs that target the peroxisome proliferator-activated receptor-[gamma] (PPAR-[gamma]).
CymaBay Therapeutics, a clinical-stage biopharmaceutical company located in the San Francisco Bay Area, has received orphan drug designation from the US Food and Drug Administration for its MBX-8025, claimed to be a potent and selective peroxisome proliferator-activated receptor delta agonist, it was reported yesterday.
Adipogenic peroxisome proliferator activated receptor gamma (PPARG), which is a nuclear receptor and transcription factor, regulates lipid metabolism by controlling the expression of various lipogenic genes, such as adipocyte fatty acid binding protein 4 (FABP4), lipoprotein lipase, acyl-CoA synthase, and fatty acid transport protein (Sarjeant and Stephens, 2012).
Peroxisome proliferator activated receptors and their ligands: nutritional and clinical implications-a review.
The agreement grants Reneo Pharmaceuticals exclusive worldwide rights to research, develop and commercialize vTv Therapeutics' selective peroxisome proliferator-activated receptor delta (PPAR-delta) program.

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