RESUMO

A one-bead-two-compound inhibitor library was synthesized by the split-mix method for the identification of inhibitors of a recombinant cysteine protease from Leishmania mexicana, CPB2.8DeltaCTE. The inhibitor library was composed of octapeptides with a centrally located reduced bond introduced by reductive amination of the resin-bound amines with Fmoc amino aldehydes. The library was screened on solid phase, and less than 1% of the library contained active compounds. The inhibitors displayed great specificity in the subsites flanking the enzyme catalytic triad with Cha and Ile/Leu preferred in P(2), Phe in P(1), Cha and Ile/Leu in P(1)', and Ile/Leu in P(2)'. Some of the inhibitors were resynthesized, and the kinetics of inhibition were determined in solution-phase assays. Most of the inhibitors had micromolar K(i) values, and a few inhibited the enzyme at nanomolar concentrations. One inhibitor, DKHF(CH(2)NH)LLVK (K(i) = 1 microm), was tested for antiparasite efficacy and shown to affect parasite survival with an IC(50) of approximately 50 microm.

Assuntos

Inibidores de Cisteína Proteinase/síntese química , Leishmania mexicana/enzimologia , Oligopeptídeos/síntese química , Aminação , Animais , Técnicas de Química Combinatória , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Avaliação Pré-Clínica de Medicamentos , Técnicas In Vitro , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Oxirredução , Polietilenoglicóis , Proteínas Recombinantes/antagonistas & inibidores , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Relação Estrutura-Atividade