Reverse Phase High Pressure Liquid Chromatography for the Separation of Peptide Hormone Diastereoisomers

Abstract

Diastereoisomers of specifically labeled oxytocin derivatives were resolved using reverse phase high pressure liquid chromatography. The peptides [1-hemi-DL-[α-²H]cystine]oxytocin, [6-hemi-DL-[α^-2H]cystine]oxytocin, [2-DL-[α^-2H]tyrosine]oxytocin and [8-DL-[2^-13C]leucine]oxytocin were readily separated using the conditions described. The diastereoisomers of the oxytocin analog [3-DL-[2^-13C]leucine]oxytocin also demonstrated baseline resolution under the same conditions. The procedure offers the investigator a rapid method for screening synthetic oxytocin peptides for undesirable diastereoisomeric by-products.