Fig. 5. (A) Separation of free nanogold from labelled protein by gel filtration (red curve). (B) Fractions of the first peak were dotted onto nitrocellulose paper and stained to detect the presence of gold and protein. The second peak (free gold without protein) did not bind to the paper. (C) Binding assays of labelled and unlabelled triple mutant tau (4R-tauTM). The curve shown is for assembly with GMPCPP; results for GTP were similar.