FACILE LIQUID-CHROMATOGRAPHIC ENANTIORESOLUTION OF NATIVE AMINO-ACIDSAND PEPTIDES USING A TEICOPLANIN CHIRAL STATIONARY-PHASE

The glycopeptide antibiotic teicoplanin is shown to be a highly effect ive stationary phase chiral selector for the resolution of underivatiz ed amino-acid and imino-acid enantiomers. Fifty four of these compound s (including all chiral protein amino acids) as well as a number of di peptides were resolved. Hydro-organic mobile phases are used and no bu ffers or added salts are needed in most cases. Hence the purified anal ytes are easily isolated in pure form, if needed, by evaporating of th e solvent. The effect of pH, organic modifier type and amount are disc ussed. The enantioselective separation mechanism is examined using bot h molecular modeling and retention data. The strongest stereoselective interaction is for carboxy-terminated D-amino-acids. In the case of p eptides, it is not necessary for these to be a D-, D-, terminal sequen ce for strong interactions. In some cases, including Ala-Ala, the L-, D- terminal sequence showed greater interaction with the teicoplanin c hiral stationary phase.