Determination of the binding sites of selected aptamers by competitive anisotropy assay.

<p>Two nM of fluorescently labeled aptamer (βB-1, βB-20, βB-19 or βB-32) was firstly incubated with 288 nM of β-BuTx, and then titrated with increasing concentrations of unlabeled aptamer βB-1. Labeled βB-1 was also titrated with unlabeled random ssDNA as control.