Fig. 5.

Characterization of total and phosphorylated S129 human alpha-synuclein duplex assay. The hook-point for biotinylated 4B12 antibody was determined simultaneously in a mix of Europium Acceptor-bead coupled 11A5 antibody and Terbium Acceptor-bead coupled LB509 antibody (a). Arrows indicate optimal 4B12 concentrations for both Acceptor-bead variants. Equivalency of the signal obtained in the total h-asyn assay was demonstrated for pS129 h-asyn and h-asyn proteins in the duplex assay in two consecutive experiments and data plotted in panel (b). All protein standards were spiked in naïve rat brain lysate. Lower detection limit (LDL) was 450 pg/ml and is indicated with a dashed line. Intra assay variation was calculated based on three standard curves which were measured on the same day but on separate plates for each emission signal separately (c and d). Inter assay variation data was calculated based on six pairs of standard curves performed on separate days (e and f). AU arbitrary units