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Interaction of N ‐(2‐Nitro‐4‐Azidophenyl)‐Serotonin with Two Types of Monoamine Oxidase in Rat Brain
Author(s) -
Chen Shiuan,
Shih Jean C.,
Xu QinPing
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb06095.x
Subject(s) - monoamine oxidase , serotonin , nap , chemistry , monoamine oxidase a , monoamine oxidase inhibitor , stereochemistry , monoamine neurotransmitter , nitro , monoamine oxidase b , substrate (aquarium) , enzyme , biochemistry , biology , receptor , neuroscience , organic chemistry , ecology , alkyl
The effects of N ‐(2‐nitro‐4‐azidophenyl) serotonin (NAP‐5‐HT) on types A and B monoamine oxidase (MAO) in rat brain cortex were studied. In the dark this compound acted as a competitive inhibitor for both types A and B MAO ( K 1 values of 0.19 μ M and 0.21 μ M for types A and B MAO, respectively). Upon photolysis, NAP‐5‐HT became an irreversible inhibitor for only type B MAO. A 50% inhibition was obtained by irradiation of the enzyme in the presence of 35 n M NAP‐5‐HT. Furthermore the inhibition of type B MAO could be protected by including its substrate phenylethylamine during the irradiation. Under the same photolytic conditions photodependent inhibition of type A MAO by NAP‐5‐HT was not clearly observed. These results provide further evidence that there is a fundamental difference in the active site of the two types of MAO in brain. NAP‐5‐HT may be a useful photoaffinity probe for characterizing the active site of type B MAO.