Figure 2.

(A) Displacement titration of HABA within streptavidin by [8]²⁺ and biotin in NaH₂PO₄ buffer (2.7 mL, 20 mm, pH 7.0). (B) Evolution of the absorbance at 475 nm upon irradiation at λ = 465 nm (Δλ _1/2 = 25 nm) of 6.0 × 10^–5 m [8]²⁺ in absence and in presence of one equivalent tetrameric streptavidin in NaH₂PO₄ buffer (3.00 mL, 20 mm, pH 7.0).