ラット唾液腺ペルオキシソームの D-アスパラギン酸オキシダーゼに関する研究

概要

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D-aspartate oxidase (EC 1.4.3.1) is a flavoprotein that catalyzes the oxidative deamination of dicarboxylic D-amino acids by O_2 with the production of H_2O_2, NH_3, and corresponding α-keto acids. The presence of D-aspartate oxidase has been reported in many mammalian tissues, showing that the enzyme differs from D-amino acid oxidase (EC 1.4.3.3), and is located in the peroxisomes of mammalian liver and kidney. However, there is no report on the properties of D-aspartate oxidase in mammalian oral glands. D-aspartate oxidase activity was detected in the homogenate of rat submandibular gland. Subcellular distribution of D-aspartate oxidase of the tissue was examined by sucrose-density gradient centrifugation. D-aspartate oxidase was found to be present in the peroxisomes with the same densities as those of mammalian liver and kidney ; the enzyme was located in the peroxisomal membrane or core. The peroxisomal enzyme was highly specific towards N-methyl-D-aspartate (NMDA) and D-aspartate out of 19 D-amino acids tested. The same results were obtained in other salivary glands (sublingual gland and parotid gland) with respect to the subcellular distribution and substrate specificity of D-aspartate oxidase. On the other hand, D-amino acid oxidase activity was not detected in the salivary glands, showing that D-aspartate oxidase is used as a peroxisomal marker in the salivary glands.
九州歯科学会の論文
2000-02-25