Figure 4

Modeling UCB binding to phosphatidylcholine vesicles at various pH values. Experimental data derived from Tipping et al., 1979 [12]. Curve A, calculated assuming pKa values for UCB of 8.12 and 8.44 and the dimerization constant for the B⁼ dianion of 0.26 μ M^-1 [4]. Curve B, calculated assuming constant maximum solubility of H₂B of 51 nM [4]. Curve C, calculated assuming pKa values of UCB of 4.2 and 4.9 [3, 17–20]. Shaded star, mid-point pH of binding curve A.