RESUMO
In search of a backup M(2) muscarinic receptor antagonist to the previously reported compound 1, we discovered compound (+)-14, which showed superior oral efficacy in animal models. The improvement of oral efficacy was achieved by modulating both the molecular weight and lipophilicity of the lead compounds.
Assuntos
Autorreceptores/antagonistas & inibidores , Fármacos do Sistema Nervoso Central/síntese química , Antagonistas Muscarínicos/síntese química , Piperidinas/síntese química , Receptores Muscarínicos/efeitos dos fármacos , Acetilcolina/metabolismo , Administração Oral , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Fármacos do Sistema Nervoso Central/química , Fármacos do Sistema Nervoso Central/farmacologia , Corpo Estriado/metabolismo , Humanos , Técnicas In Vitro , Microdiálise , Conformação Molecular , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/farmacologia , Piperidinas/química , Piperidinas/farmacologia , Ratos , Receptor Muscarínico M2 , Relação Estrutura-AtividadeRESUMO
TNF-alpha converting enzyme (TACE) is a multidomain, membrane-anchored protein that includes a Zn-dependent protease domain. It releases the soluble form of cytokine tumor necrosis factor-alpha (TNF-alpha) from its membrane-bound precursor. TACE is a metalloprotease containing a catalytic glutamic acid, Glu-406, and a Zn(2+) ion ligated to three imidazoles. The protonation states of the active site glutamic acid and inhibitors are important factors in understanding the potency of inhibitors with acidic zinc-ligating groups such as hydroxamic and carboxylic acids. Density functional methods were utilized to compute pK(a) values using a model of the catalytic site of TACE and to predict a concomitant mechanism of binding, consistent with lowering the pK(a) of the bound ligand and raising the pK(a) of the active site Glu-406. Weak acids, such as hydroxamic acids, bind in their neutral form and then transfer an acidic proton to Glu-406. Stronger acids, such as carboxylic acids, bind in their anionic form and require preprotonation of Glu-406. Similar binding events would be expected for other zinc-dependent proteases.