RESUMEN

Transient kinetics of the equine infectious anemia virus deoxyuridine 5'-triphosphate nucleotide hydrolase were characterized by monitoring the fluorescence of the protein. Rate constants for the association and dissociation of substrate and inhibitors were determined and found to be consistent with a one-step mechanism for substrate binding. A C-terminal part of the enzyme presumed to be flexible was removed by limited trypsinolysis. As a result, the activity of the dUTPase was completely quenched, but the rate constants and fluorescent signal of the truncated enzyme were affected only to a minor degree. We conclude that the flexible C-terminus is not a prerequisite for substrate binding, but indispensable for catalysis.

Asunto(s)

Nucleótidos de Desoxiuracil/metabolismo , Virus de la Anemia Infecciosa Equina/enzimología , Pirofosfatasas/metabolismo , Animales , Fluorescencia , Caballos , Cinética , Ligandos , Especificidad por Sustrato

Asunto(s)

Antimetabolitos Antineoplásicos/toxicidad , División Celular/efectos de los fármacos , Nucleótidos de Desoxiuracil/toxicidad , Pirofosfatasas/antagonistas & inhibidores , Línea Celular , Ensayos de Selección de Medicamentos Antitumorales , Glioma , Humanos , Recién Nacido , Linfoma , Masculino , Melanoma , Piel , Relación Estructura-Actividad , Células Tumorales Cultivadas