Distribution and characteristics of D-amino acid and D-aspartate oxidases in fish tissues.
Distribution and characteristics of D-amino acid and D-aspartate oxidases in fish tissues.
复制标题
D-氨基酸和D-天冬氨酸氧化酶在鱼类组织中的分布和特征。
DOI：
10.1002/jez.a.10217
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
H. Abe
中科院分区：
文献类型：
--
作者：
M. G. Sarower;T. Matsui;H. Abe
研究了D-氨基酸氧化酶(D-Aao，EC 1.4.3.3)和D-天冬氨酸氧化酶(D-Aspo，EC 1.4.3.1)活性在不同鱼种组织中的分布。这两种酶的活性在肾脏和肝脏中普遍较高，在肠道中较低，但也有一些例外。给鲤鱼灌胃5微克/克体重(-1)天(-1)的D-丙氨酸30天后，肠道、肝胰腺和肾脏的D-AAO活性分别增加了8倍、3倍和1.5倍，而脑中的D-AAO活性没有增加。相比之下，口服D-谷氨酸或D-天冬氨酸没有显示任何组织中D-Aspo活性的增加。鲤鱼肾和肝胰腺的D-Aao和D-Aspo定位于过氧化体的亚细胞内，这在哺乳动物中是明确的。虹鱼肾、鲤鱼肾和肝胰腺中D-AAO的最适底物为D-脯氨酸，其次是D-丙氨酸和D-苯丙氨酸。N-甲基-D-天冬氨酸是虹鱼肾脏和鲤鱼肝胰脏D-天冬氨酸的最佳底物。虹鱼肾中D-AAO的最适pH为7.4~8.2，而D-Aspo的最适pH约为10。D-AAO被称为D-AAO抑制剂的苯甲酸盐抑制，而D-Aspo被D-Aspo抑制剂中的酒石酸强烈抑制。根据这些结果，至少鱼类中的D-AAO被认为是外源和内源游离D-丙氨酸的代谢剂，D-丙氨酸在甲壳类和双壳类等水生无脊椎动物中含量丰富，是这些鱼类的潜在食物来源。
The distributions of D-amino acid oxidase (D-AAO, EC 1.4.3.3) and D-aspartate oxidase (D-AspO, EC 1.4.3.1) activities were examined on several tissues of various fish species. Both enzyme activities were commonly high in kidney and liver and low in intestine with some exceptions. After oral administration of D-alanine at 5 micromol /g body weight(-1)day(-1) to carp for 30 days, D-AAO activity increased by about 8-, 3-, and 1.5-fold in intestine, hepatopancreas, and kidney, respectively, whereas no increase was found in brain. In contrast, oral administration of D-glutamate or D-aspartate did not show any increase of D-AspO activity in any tissues. D-AAO and D-AspO of common carp kidney and hepatopancreas were subcellularly localized in peroxisomes, as clarified in mammals. D-proline was the best substrate for D-AAO in rainbow trout kidney, common carp kidney, and hepatopancreas, followed by D-alanine and D-phenylalanine. N-methyl-D-aspartate was the best substrate for D-AspO in rainbow trout kidney and common carp hepatopancreas. The optimal pH for D-AAO in rainbow trout kidney was broad, from 7.4 to 8.2, and that for D-AspO was around 10. D-AAO was inhibited by benzoate known as D-AAO inhibitor and D-AspO was strongly inhibited by meso-tartarate as D-AspO inhibitor. From these results, at least D-AAO in fish is considered to work as a metabolizing agent of exogenous and endogenous free D-alanine that is abundant in aquatic invertebrates such as crustaceans and bivalve mollusks, which are potential food sources of these fishes.