Determination of binding constants between the antibiotic ristocetin A and D-Ala-D-Ala terminus peptides by affinity capillary electrophoresis

Binding constants between the antibiotic ristocetin A (Rist A) and D-Ala-D-Ala terminus peptides were determined using affinity capillary electrophoresis (ACE). in these experiments two techniques are used to obtain binding constants. In the first, a plug of Rist A and non-interacting standards are injected and electrophoresed. Analysis of the change in the relative migration time ratio (RMTR) of Rist, relative to the non-interacting standards, as a function of the concentration of peptide, yields a value for the binding constant (K-b). in the second, samples of peptide and standards ore injected and electrophoresed in increasing concentrations of Rist A in the running buffer. Analysis using the RMTR yields a K-b. The findings described here demonstrate the advantage of using ACE for estimating binding parameters between antibiotics and ligands.