Chen S, Shih J C, Xu Q P
J Neurochem. 1985 Sep;45(3):940-5. doi: 10.1111/j.1471-4159.1985.tb04084.x.
We had previously shown that 4-fluoro-3-nitrophenyl azide (FNPA) is a competitive inhibitor of both types of monoamine oxidase (MAO) in the dark, but it is a preferential photoaffinity label for only the type B MAO (MAO-B). Recently we synthesized a number of arylazido compounds with structures related to FNPA and determined the effects of these compounds on the two types of MAO in rat brain cortex. We found that the fluoro group of FNPA was not required for the inhibition of MAO activities because neither the presence nor the position of the fluoro group affected its inhibition of MAO. On the other hand, both the nitro and the azido groups of FNPA were shown to be important for FNPA inactivation of two types of MAO. The inhibitory potency was significantly lower for compounds without either group. Furthermore, we found that all nitrophenyl azide isomers except 2-nitrophenyl azide were photodependent inhibitors of MAO-B. Under the same experimental conditions none of the compounds photoinactivated MAO-A. On the basis of these findings, mechanisms for FNPA inhibition of the two types of MAO are discussed.
我们之前已经表明，4-氟-3-硝基苯基叠氮化物（FNPA）在暗处是两种单胺氧化酶（MAO）的竞争性抑制剂，但它只是B型单胺氧化酶（MAO-B）的优先光亲和标记物。最近我们合成了一些与FNPA结构相关的芳基叠氮化合物，并测定了这些化合物对大鼠脑皮质中两种MAO的影响。我们发现，FNPA的氟基团对于抑制MAO活性并非必需，因为氟基团的存在与否及其位置均不影响其对MAO的抑制作用。另一方面，FNPA的硝基和叠氮基团对于两种MAO的FNPA失活均很重要。对于没有任何一个基团的化合物，其抑制效力显著降低。此外，我们发现除2-硝基苯基叠氮化物外，所有硝基苯基叠氮化物异构体都是MAO-B的光依赖性抑制剂。在相同实验条件下，没有一种化合物能使MAO-A发生光失活。基于这些发现，我们讨论了FNPA抑制两种MAO的机制。
