On‐column derivatization of the antibiotics teicoplanin and ristocetin coupled to affinity capillary electrophoresis

Abstract

Binding constants between the glycopeptides teicoplanin (Teic) and ristocetin (Rist) and their derivatives to D-Ala-D-Ala terminus peptides were determined by on-column receptor synthesis coupled to partial-filling affinity capillary electrophoresis (PFACE) or affinity capillary electrophoresis (ACE). In these techniques, the column is first partially filled with increasing concentrations of D-Ala-D-Ala terminus peptides. This is followed by plugs of buffer, antibiotic and two noninteracting standards, and acetic and/or succinic anhydride (and buffer in the case of ACE). The order of the reagent plugs containing the antibiotic and anhydride varies with the charge of the glycopeptide. Upon electrophoresis, the antibiotic reacts with the anhydride yielding a derivative of Teic or Rist. Continued electrophoresis results in the overlap of the derivatized antibiotic and the plug of D-Ala-D-Ala peptide. Analysis of the change in the relative migration time ratio (RMTR) of the new glycopeptide relative to the standards, as a function of the concentration of the D-Ala-D-Ala ligand yields a value for the binding constant K(b). The techniques described here can be used to assess how the derivatization of drugs alters their affinities for target molecules.

Recent developments in capillary electrophoresis and capillary electrochromatography of peptides

“…, and its on-column modified derivative [62]. Other new modifications of PF-CAE involve flowthrough PF-CAE, competitive flow-through PF-CAE, and multiple-step ligand injection PF-CAE [129,130].…”

“…This freshly synthesized ligand meets later on in the capillary zone of glycopeptide antibiotics (vancomycin, ristocetin, or teicoplanin) and from the changes of the migration time of this ligand and that of the analyte noninteracting with vancomycin, the binding constant between the ligand and vancomycin can be estimated. Similarly, two glycopeptide antibiotics, teicoplanin and ristocetin, have been on-column derivatized by acetic or succinic anhydride and the binding of these derivatives with D-Ala-D-Ala terminus peptides have been studied [61,62].…”

Investigation of the stereodynamics of molecules and catalyzed reactions by CE

“…In this publication, derivatization was carried out with 7-fluorobenzofurazan-4-sulfonamide (ABD-F) in the capillary. Gomez and Zhang [179] used on-column reaction electrophoresis to determine binding constants between the glycopeptides teicoplanin and ristocetin to D-Ala-D-Ala terminus peptides by on-column receptor synthesis coupled to (partial filling) affinity CE. Kang and Cheng [180] developed a method to estimate the enantiomeric excess ee of chiral amino compounds by MEKC is described.…”

Recent advances in capillary electrophoresis and capillary electrochromatography of peptides

“…In the acid BGE, 100 mM ammonium formic acid, pH 2.7, the expression q/M r 0. 56 , where q is the calculated net charge and M r is the relative molecular mass, provided the best correlation with the electrophoretic mobility of the tested peptides, see Fig. 2.…”

“…This freshly synthesized ligand meets later on in the capillary zone of vancomycin and from the changes of the migration time of this ligand and that of the analyte non-interacting with vancomycin, the binding constant between the ligand and vancomycin can be estimated. Similarly, the glycopeptide antibiotics, teicoplanin and ristocetin, have been on-column derivatized by acetic or succinic anhydride and the binding of these derivatives with DAla-D-Ala terminus peptides has been studied [56].…”