USE OF CAPILLARY ZONE ELECTROPHORESIS IN AN INVESTIGATION OF PEPTIDE UPTAKE BY DAIRY STARTER BACTERIA

A capillary zone electrophoresis (CZE) method to separate the peptide series val-gly(n), where n is 1 to 4, has been evaluated and compared to separation by reversed-phase high-performance liquid chromatography (RP-HPLC). The method was able to quantitate peptides present at very low concentrations (down to 0.05 mM) with high reproducibility and ac curacy and was capable of separating peptides differing in size by onl y a single glycine residue. It could also separate the peptides val-gl y and leu-gly which differed in only a single side-chain methylene gro up. The method was fast, required small sample volumes, and proved to be superior to RP-HPLC. The suitability of the CZE method to analyze p eptide uptake by dairy starter bacteria is discussed.