Binding of dipeptides and amino acids to Teicoplanin chiral stationary phase: apparent homogeneity of some heterogeneous systems.
The binding between Teicoplanin glycopeptide antibiotic and some dipeptides and amino acids has been studied by nonlinear liquid chromatography. A Teicoplanin-based chiral stationary phase, specifically designed to achieve maximum selectivity and loading by reducing non-specific interactions, has been prepared and packed into a microbore column. The adsorption isotherms of the enantiomers of proline, alanine, and alanine-alanine (Ala-Ala) have been measured through frontal analysis. The experimental binding data have been interpreted in the context of the ordinary homogeneous Michaelis-Menten model and by considering an heterogeneous model that accounts for a broad adsorption energy distribution (AED). AED has been achieved by the analysis of adsorption isotherms. Besides confirming the importance of the terminal D-Ala-D-Ala moiety in the molecular recognition between the dipeptide and the macrocyclic antibiotic Teicoplanin (it was found that Teicoplanin behaves as a molecular filter toward the enantiomers of Ala-Ala), this study shows that a heterogeneous adsorption model is needed for the correct interpretation of binding data.
Cavazzini
Alberto
A
Department of Chemistry, University of Ferrara, via L. Borsari 46, I-44100 Ferrara, Italy. cvz@unife.it
Pasti
Luisa
L
Dondi
Francesco
F
Finessi
Marco
M
Costa
Valentina
V
Gasparrini
Francesco
F
Ciogli
Alessia
A
Bedani
Filippo
F
D000327:Adsorption; D000596:Amino Acids / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D004151:Dipeptides / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D013237:Stereoisomerism; D017334:Teicoplanin / Q000737:chemistry*; D013816:Thermodynamics
D000596:Amino Acids; D004151:Dipeptides; D017334:Teicoplanin