Separation of cis/trans isomers of a prolyl peptide bond by capillary zone electrophoresis

✍ Scribed by Sylke Meyer; Andreas Jabs; Mike Schutkowski; Pro. Dr. Gunter Fischer

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 697 KB
• Volume: 15
• Category: Article
• ISSN: 0173-0835
• DOI: 10.1002/elps.11501501174

✦ Synopsis

Abstract

On capillary electrophoresis of the chemically pure thioxo peptide Ala‐Phe‐ψ[CS‐N]‐Pro‐Phe‐4‐nitroanilide a peak splitting was observed at a capillary temperature of 25°C. By contrast, the oxo peptide analogue exhibits a single, sharp peak under these conditions. Both peaks of the thioxo compound coincided gradually when the temperature was increased to 60°C. Peak fusion was reverted by cooling down the heated sample. This behavior could be attributed to the electrophoresis‐mediated separation of the cis/trans prolyl bond isomers of the thioxo peptide, allowing data of this conformational equilibrium to be determined. Derived from computational data about molecular volume and the hydration energy of low‐energy cis and trans isomeric structures, the more rapid migration of the cis form in comparison to trans may be explained by structural parameters.