May S W, Young F K, Powers J L, Gill-Woznichak M M
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta 30332, USA.
Biochem Biophys Res Commun. 1996 Nov 12;228(2):278-84. doi: 10.1006/bbrc.1996.1653.
Dopamine beta-monoxygenase (DBM, E.C. 1.14.17.1) is an attractive target point for possible modulation of adrenergic activity, and a variety of DBM-targeted pseudosubstrates and inhibitors have been developed in this laboratory and other laboratories. We now demonstrate the efficacy of a DBM-targeted mechanism-based inactivator, as well as enzymatic processing of two alternate DBM substrates, within functional adrenal chromaffin cells. When cultured adrenal medullary chromaffin cells were incubated with the mechanism-based inactivator 1-(4'-hydroxyphenyl)-1-(aminomethyl)-ethene (HOPAME), vesicular DBM activity was markedly decreased. Similarly, the alternate substrates 4'-hydroxyphenyl-2-aminoethyl sulfide and 4'-hydroxyphenyl-2-aminopropyl selenide each undergo uptake and DBM-catalyzed oxygenation within these cells. The simultaneous action of both the mechanism-based inactivator and an alternate substrate within functional chromaffin cells was also demonstrated. These results provide support for a direct mechanistic link between the enzymological properties of DBM-targeted adrenergic agents and their in-vivo pharmacological activities.
多巴胺β-单加氧酶（DBM，E.C. 1.14.17.1）是调节肾上腺素能活性潜在的理想靶点，本实验室及其他实验室已开发出多种靶向DBM的假底物和抑制剂。我们现在证明了一种基于DBM作用机制的失活剂在功能性肾上腺嗜铬细胞中的有效性，以及两种替代DBM底物的酶促加工过程。当将培养的肾上腺髓质嗜铬细胞与基于作用机制的失活剂1-（4'-羟基苯基）-1-（氨基甲基）乙烯（HOPAME）一起孵育时，囊泡DBM活性显著降低。同样，替代底物4'-羟基苯基-2-氨基乙基硫化物和4'-羟基苯基-2-氨基丙基硒化物在这些细胞内均会发生摄取及DBM催化的氧化反应。还证明了基于作用机制的失活剂和替代底物在功能性嗜铬细胞中的同时作用。这些结果为靶向DBM的肾上腺素能药物的酶学性质与其体内药理活性之间的直接机制联系提供了支持。
