Kandaswami C, D'Iorio A
Can J Biochem. 1979 Jun;57(6):588-94. doi: 10.1139/o79-074.
A marked decrease in liver mitochondrial monoamine oxidase activity was noticed in rats fed a fat-free diet as compared with that of their controls. In lipid-deprived rats, the specific activity of this enzyme was very low towards different substrates studied. The activity of kynurenine 3-monooxygenase, which like monoamine oxidase is localized on the mitochondrial outer membrane, was similarly depressed under conditions of lipid deprivation. On the other hand no major changes were observed in the activity of the inner membrane enzyme, kynurenine amino-transferase. Mitochondria from fat-free diet-fed rats were deficient in essential fatty acids whereas no appreciable variations were found in the relative proportions of phospholipids in comparison with those of control mitochondria. Mitochondrial monoamine oxidase activity of the deficient rats retained its sensitivities to inhibitor drugs like clorgyline and deprenyl. No changes were noticeable in the substrate specificity of monoamine oxidase in these rats. When we switched the fat-free diet-fed rats to a diet supplemented with a source of essential fatty acids, there was an elevation in the activities of both monoamine oxidase and kynurenine 3-monooxygenase, their levels approaching those of the control rats.
与对照组相比，喂食无脂饮食的大鼠肝脏线粒体单胺氧化酶活性显著降低。在脂质缺乏的大鼠中，该酶对所研究的不同底物的比活性非常低。与单胺氧化酶一样定位于线粒体外膜的犬尿氨酸3-单加氧酶的活性，在脂质缺乏的条件下也同样受到抑制。另一方面，内膜酶犬尿氨酸氨基转移酶的活性未观察到重大变化。喂食无脂饮食的大鼠的线粒体缺乏必需脂肪酸，而与对照线粒体相比，磷脂的相对比例没有明显变化。缺乏必需脂肪酸的大鼠的线粒体单胺氧化酶活性对氯吉兰和司来吉兰等抑制剂药物仍保持敏感性。这些大鼠中单胺氧化酶的底物特异性没有明显变化。当我们将喂食无脂饮食的大鼠改为补充必需脂肪酸来源的饮食时，单胺氧化酶和犬尿氨酸3-单加氧酶的活性均升高，其水平接近对照大鼠。
