Reference

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. Chen, Shiuan; Shih, Jean Chen; Xu, Qiu Ping (Sch. Pharm., Univ. South. California, Los Angeles, CA 90033, USA). Biochem. Pharmacol., 34(6), 781-8 (English) 1985. CODEN: BCPCA6. ISSN: 0006-2952. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Section cross-reference(s): 1 The effects of 4-fluoro-3-nitrophenyl azide (FNPA) [28166-06-5] on types A and B monoamine oxidase (MAO) [9001-66-5] in rat brain cortex were studied using serotonin [50-67-9] and phenylethylamine [64-04-0] as substrates, resp. FNPA competitively inhibited the oxidative deamination of both serotonin (Ki = 3 mM) and phenylethylamine (Ki = 0.78 mM) in the dark. Upon photoirradn. 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 mixt. Addnl. evidence for the photoinduced covalent binding of FNPA to type B MAO is that noncompetitive 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 exptl. conditions, only minimal photodependent inhibition of type A MAO by FNPA was found. The obsd. differences in the efficiencies of the photodependent inactivation of the 2 types of MAO by FNPA suggests that there is a conformational or a structural difference in the active sites of the 2 types of MAO. The active site of type B MAO could be characterized by utilizing FNPA as a photoaffinity labeling probe.

Inhibition of monoamine oxidase by phenyl azides

Inhibition of monoamine oxidase by phenyl azides. Chen, Shiuan; Shih, Jean C.Chemical with cas number 28166-06-5 also plays role.; Xu, Qiuping (Sch. Pharm., Univ. Southern California, Los Angeles, CA 90033, USA). J. Neurochem., 45(3), 940-5 (English) 1985. CODEN: JONRA9. ISSN: 0022-3042. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Section cross-reference(s): 7 A no. of arylazido compds. with structures related to 4-fluoro-3-nitrophenyl azide (FNPA)(I) [28166-06-5] were synthesized and the effects of these compds. on the 2 types of MAO [9001-66-5] in rat brain cortex were detd. The fluoro group of FNPA was not required for the inhibition of MAO activities because neither the presence nor the postion of the fluoro group affected its inhibition of MAO. On the other hand, both the nitro and the azido groups of FNPA were important for FNPA inactivation of 2 types of MAO. The inhibitory potency was significantly lower for compds. without either group. Furthermore, all nitrophenyl azide isomers except 2-nitrophenyl azide were photodependent inhibitors of MAO-B. Under the same exptl. conditions none of the compds. photoinactivated MAO-A. On the basis of these findings, mechanisms for FNPA inhibition of the 2 types of MAO are discussed. .