peroxisome

enUK

Peroxisome

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.

peroxisome

[pə′räk·sə‚sōm] (cell and molecular biology) Any of a subclass of microbodies that contain at least four enzymes involved in the metabolism of hydrogen peroxide.

peroxisome

enUK

peroxisome

[pĕ-roks´ĭ-sōm] a microbody found in vertebrate animal cells, especially kidney and liver cells, that contains urate oxidase, amino acid oxidase, catalase, and other enzymes.

pe·rox·i·some

(pĕ-rok'si-sōm), A membrane-bound organelle occurring in many eukaryotic cells that often has an electron-dense crystalline inclusion containing catalase, urate oxidase, and other oxidative enzymes relating to the formation and degradation of H₂O₂; thought to be important in detoxifying various molecules and in catalyzing the breakdown of fatty acids to acetyl-CoA; an absence of peroxisomes is found in patients with Zellweger syndrome. [peroxide + G. sōma, body]

peroxisome

(pə-rŏk′sĭ-sōm′)n. A cell organelle containing a large number of enzymes, including catalase and oxidase, that break down long-chain fatty acids and other organic molecules. The hydrogen peroxide produced by these reactions is also broken down within the peroxisome.

per·ox′i·som′al (-sō′məl) adj.

pe·rox·i·some

(pĕr-ok'si-sōm) A membrane-bound organelle occurring in nearly all eukaryotic cells that often contains oxidative enzymes relating to the formation and degradation of H₂O₂.
Synonym(s): microbody. [peroxide + G. sōma, body]

peroxisome

an organelle of EUKARYOTE cells which is surrounded by a single unit membrane. Peroxisomes contain PEROXIDASES and may be concerned with the production of molecular oxygen from the breakdown of hydrogen peroxide. They are located near MITOCHONDRIA and plant CHLOROPLASTS, and appear to be involved in CELLULAR RESPIRATION.

单词	peroxisome
释义	peroxisome enUK per·ox·i·some P0202900 (pə-rŏk′sĭ-sōm′)n. A cell organelle containing a large number of enzymes, including catalase and oxidase, that break down long-chain fatty acids and other organic molecules. The hydrogen peroxide produced by these reactions is also broken down within the peroxisome. [peroxi(de) + -some.] per·ox′i·som′al (-sō′məl) adj. peroxisome (pəˈrɒksɪˌsəʊm) n (Biochemistry) biology a type of organelle present in most eukaryotic cells that carry out oxidative reactions, such as oxidation of alcohol in the liver peroxisome enUK Peroxisome 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. peroxisome [pə′räk·sə‚sōm] (cell and molecular biology) Any of a subclass of microbodies that contain at least four enzymes involved in the metabolism of hydrogen peroxide. peroxisome enUK peroxisome [pĕ-roks´ĭ-sōm] a microbody found in vertebrate animal cells, especially kidney and liver cells, that contains urate oxidase, amino acid oxidase, catalase, and other enzymes. pe·rox·i·some (pĕ-rok'si-sōm), A membrane-bound organelle occurring in many eukaryotic cells that often has an electron-dense crystalline inclusion containing catalase, urate oxidase, and other oxidative enzymes relating to the formation and degradation of H₂O₂; thought to be important in detoxifying various molecules and in catalyzing the breakdown of fatty acids to acetyl-CoA; an absence of peroxisomes is found in patients with Zellweger syndrome. [peroxide + G. sōma, body] peroxisome (pə-rŏk′sĭ-sōm′)n. A cell organelle containing a large number of enzymes, including catalase and oxidase, that break down long-chain fatty acids and other organic molecules. The hydrogen peroxide produced by these reactions is also broken down within the peroxisome. per·ox′i·som′al (-sō′məl) adj. pe·rox·i·some (pĕr-ok'si-sōm) A membrane-bound organelle occurring in nearly all eukaryotic cells that often contains oxidative enzymes relating to the formation and degradation of H₂O₂. Synonym(s): microbody. [peroxide + G. sōma, body] peroxisome an organelle of EUKARYOTE cells which is surrounded by a single unit membrane. Peroxisomes contain PEROXIDASES and may be concerned with the production of molecular oxygen from the breakdown of hydrogen peroxide. They are located near MITOCHONDRIA and plant CHLOROPLASTS, and appear to be involved in CELLULAR RESPIRATION.
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