4-Fluoro-3-nitrophenyl azide, a selective photoaffinity label for type B monoamine oxidase.
4-Fluoro-3-nitrophenyl azide, a selective photoaffinity label for type B monoamine oxidase.
复制标题
4-氟-3-硝基苯基叠氮化物，B 型单胺氧化酶的选择性光亲和标记。
DOI：
10.1016/0006-2952(85)90758-0
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发表时间：
1985
影响因子：
5.8
通讯作者：
Xu,QP
中科院分区：
文献类型：
--
作者：
Chen,S;Shih,JC;Xu,QP
以5-羟色胺和苯乙胺为底物，研究了4-氟-3-硝基苯叠氮（FNPA）对大鼠大脑皮层A型和B型单胺氧化酶的影响。FNPA在黑暗中竞争性抑制5-羟色胺（Ki= 3μM）和苯乙胺（Ki= 0.78μM）的氧化脱氨。在FNPA的存在下，光照射后，B型单胺氧化酶活性的光依赖性抑制。这种光依赖性抑制显然是不可逆的，因为在洗涤光解的FNPA-酶混合物时没有恢复活性。FNPA与B型MAO的光诱导共价结合的另外证据是，光解后产生非竞争性抑制动力学。苯乙胺的保护作用和FNPA光解酶后[3 H]帕吉林标记的减少显示了FNPA对B型MAO的光依赖性掺入的特异性。在相同的实验条件下，FNPA对A型单胺氧化酶的光依赖性抑制作用很小，FNPA对两种单胺氧化酶光依赖性失活效率的差异表明，两种单胺氧化酶的活性位点存在构象或结构上的差异。利用FNPA作为光亲和标记探针可以表征B型MAO的活性位点。
The effects of 4-fluoro-3-nitrophenyl azide (FNPA) on types A and B monoamine oxidase in rat brain cortex were studied using serotonin and phenylethylamine as substrates respectively. FNPA competitively inhibited the oxidative deamination of both serotonin (Ki= 3μM) and phenylethylamine (Ki= 0.78μM) in the dark. Upon photoirradiation in the presence of FNPA, a photodependent inhibition of type B MAO activity resulted. This photodependent inhibition was apparently irreversible since there was no recovery of activity upon washing of the photolyzed FNPA-enzyme mixture. Additional evidence for the photoinduced covalent binding of FNPA to type B MAO is that non-competitive inhibition kinetics resulted after photolysis. The specificity of the photodependent incorporation of FNPA to type B MAO was shown by the protective effect of phenylethylamine and by decreased [3H]pargyline labeling after the enzyme was photolyzed with FNPA. Under the same experimental conditions, only minimal photodependent inhibition of type A MAO by FNPA was found. The observed difference in the efficiencies of the photodependent inactivation of the two types of MAO by FNPA suggests that there is a conformational or a structural difference in the active sites of the two types of MAO. The active site of type B MAO could be characterized by utilizing FNPA as a photoaffinity labeling probe.