Figure 2.

Binding of MPT to gephyrin and to its two domains. The binding of 5–157 nM MPT, isolated from denatured xanthine oxidase, to 100 nM gephyrin (♦), MogA domain (○), and MoeA-domain (□) was analyzed by using gel filtration followed by HPLC analysis of Form A, the I₂/KI-oxidation product of MPT, as described (13). Data were collected from binding experiments with six different MPT concentrations. Dissociation constants (K_d), maximal concentration of binding sites (n), and Hill coefficients (n_H) are shown for each curve. In the case of cooperative types of binding (gephyrin, MoeA domain), no saturation with MPT was reached. Curve regressions with n = 100 nM (equimolar binding) gave K_d values and Hill coefficients that are shown in brackets.