鳥類ペルオキシソームの Alanine : Glyoxylate Aminotransferase に関する研究
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Alanine : glyoxylate aminotransferase (AGT) is the only known aminotransferase in animal peroxisomes. In mammals, AGT is present in the peroxisomes or mitochondria. Detoxication of glyoxylate to glycine in humans is catalyzed by liver peroxisomal AGT. The primary hyperoxaluria type I, a metabolic disease characterized by a continuous urinary excretion of oxalate, is caused by a defect of peroxisomal AGT. All of mammalian AGT is present as the holo form. However, in chick embryonic liver, AGT is present as the apo form (inactive form) in the peroxisomes and glyoxylate accumulates in the liver [Noguchi et al. (1984) J. Biol. Chem., 259, 14498-14504]. These results suggest that one of the function of avian peroxisome is also detoxication of glyoxylate. To clarify it, subcellular localization, intracellular form and enzymatic and immunological properties of AGT in different bird livers were examined. 1. Aves were found to be classified into two groups on the basis of intraperoxisomal form of hepatic AGT. 2. In group 1, AGT is present as the holo form in the peroxisomes. In group 2, AGT is present as the apo form in the peroxisomes. In the mitochondria, AGT was present as the holo form in both groups. Pigeon, sparrow, Java sparrow, Japanese mannikin, canary, goose and duck were classified into group 1 and white leghorn, bantam, pheasant and Australian budgerigar into group 2. 3. The peroxisomal holo AGT was purified from pigeon liver as the representative of group 1 and peroxisomal apo AGT from chicken liver as the representative of group 2. The pigeon and chicken peroxisomal enzymes did not cross-react immunologically and differed in enzymatic properties. 4. Pigeon liver holo AGT and chicken liver apo AGT were different from mammalian liver AGT 1 and AGT 2 in immunological properties. 5. Pigeon liver mitochondrial holo AGT was immunologically cross-reactive with chicken liver mitochondrial holo AGT and mammalian liver AGT 2. 6. The same experiments were carried out with the kidney, only other tissue with AGT in animals. AGT is present as the holo form in pigeon kidney, and as the apo form in chicken kidney. These results were identical with those with the liver, suggesting that aves are classified into two groups on the basis of intraperoxisomal form of AGT in the kidney as well as in the liver.
- 九州歯科学会の論文
- 1991-06-25
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関連論文
- 鳥類ペルオキシソームの Alanine : Glyoxylate Aminotransferase に関する研究 : 主論文の要旨
- 鳥類ペルオキシソームの Alanine : Glyoxylate Aminotransferase に関する研究