FIGURE 4.

Binding experiments by SPR. The interaction of Aβ with the two stefin B iso-forms (Tyr³¹ and Glu³¹ stefin B) and isolated oligomers of the wild-type Glu³¹ stefin B were assessed at 5 μl/ml in PBS buffer, pH 7.3. A, binding of Tyr³¹ stefin B (analyte) to chip-immobilized Aβ. The concentration of Tyr³¹ stefin B was 0.5, 1, 2, 4, and 20 μm (from bottom to top). B, binding of 10 μm Aβ to chip-immobilized Tyr³¹ stefin B. C, binding of monomers (curve a), dimers (b), tetramers (c), and higher oligomers of wild-type Glu³¹ stefin B (d) to chip-immobilized Aβ. All forms were assessed at 100 μm. D, binding of the isolated tetramers of wild-type Glu³¹ stefin B at 10, 25, 50, and 100 μm (from bottom to top).