PREPARATION, APPLICATION AND BIOLOGICAL CHARACTERIZATION OF INTERLEUKIN-1-BETA MUTANT PROTEIN BIOTINYLATED AT A SINGLE SITE

Selective biotinylation of human interleukin-1β was achieved by reaction of an interleukin-1β mutant protein containing a surface-accessible cysteine with maleimido-biotin. A defined interleukin-1β derivative biotinylated at a single site was obtained. This compound retained full affinity for both the interleukin-1 receptor and streptavidin or avidin; however, its biological activity was significantly reduced in proliferative assays. Biotinylated interleukin-1β mutant protein bound to fluorescein-labelled avidin was used in flow cytometric analysis of interleukin-1 receptors. Internalization of the complex between biotinylated interleukin-1β mutant protein and streptavidin in a murine thymoma cell line was demonstrated. © 1990.