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The Physiological Role of Flavin-dependent Oxidases in Mammalian Peroxisome

哺乳动物过氧化物酶体中黄素依赖性氧化酶的生理作用

基本信息

批准号：
63570112
负责人：
HORIIKE Kihachiro
金额：
$ 1.41万
依托单位：
Shiga University of Medical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Adducts of sulfhydryl compounds and glyoxylate are substrates for the flavooxidases in peroxisome. The products can be hydrolyzed to oxalyl thiol ester which is proposed to be a metabolic effector. On the other hand, the activities of certain enzymes and receptors can be modulated by thiol/disulfide exchange reactions. The intracellular thiol/disulfide status appears to play an important role in cellular regulations and responses.Thiazolidine-2-carboxylate (TC), an adduct of cysteamine and glyoxylate, is a substrate for D-amino acid oxidase (DAO). The histochemical localizations of TC oxidase activity in various tissues of rat were in accord with those of DAO. Both oxidase activities were histochemically and biochemically shown to be due to the same enzyme, DAO. The activity of DAO was localized exclusively in the lower brain stem, cerebellum and spinal cord, and to be present only in astrocytes and Bergmann glial cells, but not in other types of glial cells, neurons, endothelial cells or ependymal cells. The greater proportion of DAO activity was present in the glial spaces around various kinds of synapses, whereas D-aspartate oxidase activity was found in the endbrain in which DAO activity was not detectable, suggesting that the distribution of the two oxidases is supplementary in brain. On the other hand, the direct actions of sulfhydryl compounds such as cysteamine to vascular smooth muscle and membrane-bound phospholipase A_2 were also investigated. From these results, the possibility is suggested that peroxisomal flavooxidases are involved in the cellular regulations by participating in metabolisms of sulfhydryl compounds and biosynthesis of oxalyl thiol ester.

巯基化合物和乙醛酸盐的加合物是过氧化物酶体中黄酮氧化酶的底物。该产物可以水解成草酰硫羟酸酯，其被认为是代谢效应物。另一方面，某些酶和受体的活性可以通过硫醇/二硫键交换反应来调节。细胞内硫醇/二硫化物状态似乎在细胞调节和反应中发挥着重要作用。噻唑烷-2-羧酸酯 (TC) 是半胱胺和乙醛酸盐的加合物，是 D-氨基酸氧化酶 (DAO) 的底物。 TC氧化酶活性在大鼠各组织中的组织化学定位与DAO的组织化学定位一致。组织化学和生物化学显示这两种氧化酶活性均归因于相同的酶 DAO。 DAO 的活性仅存在于下脑干、小脑和脊髓，并且仅存在于星形胶质细胞和伯格曼神经胶质细胞中，而不存在于其他类型的神经胶质细胞、神经元、内皮细胞或室管膜细胞中。较大比例的DAO活性存在于各种突触周围的神经胶质间隙中，而D-天冬氨酸氧化酶活性存在于端脑中，其中未检测到DAO活性，这表明这两种氧化酶在大脑中的分布是补充的。另一方面，还研究了半胱胺等巯基化合物对血管平滑肌和膜结合磷脂酶A_2的直接作用。从这些结果来看，过氧化物酶体黄酮氧化酶可能通过参与巯基化合物的代谢和草酰硫羟酸酯的生物合成来参与细胞调节。