Determination of Binding Constants between Teicoplanin and D-ala-d-ala Terminus Peptides by Affinity Capillary Electrophoresis

Binding constants between the glycopeptide antibiotic, Teicoplanin (Teic), and D-Ala-D-Ala terminus peptides were determined by affinity capillary electrophoresis (ACE) and by on-column ligand synthesis coupled to ACE. In the first technique, a plug of Teic and two non-interacting standards are injected and electrophoresed. Analysis of the change in the relative migration time ratio (RMTR) of Teic, relative to the non-interacting standards, as a function of the concentration of D-Ala-D-Ala peptide, yields a value for the binding constant. In the second technique, 9-fluorenylmethoxycarbonyl (Fmoc)-amino acid-DAla-D-Ala species are first synthesized on-column. The initial sample plug contains a D-Ala-D-Ala terminus peptide and two non-interacting standards. Plugs two and three contain solutions 1677 J. LIQ. CHROM. & REL. TECHNOL., 25(10&11), 1677–1691 (2002) Copyright # 2002 by Marcel Dekker, Inc. www.dekker.com *Corresponding author. E-mail: [email protected] ©2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc. MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016