ABSTRACT
Diastereoisomers of peptides with biological activities often exhibit pronounced antagonistic or agonistic properties which differ greatly from each other. This fact, as well as the difficulty in obtaining many uncommon amino acids in optically pure form, underlies the importance of having at hand effective chromatographic methods for the purification and characterization of diastereoisomeric mixtures of peptides. Diastereoisomeric peptides, isomers in which one or more asymmetric centers have opposite configuration, may possess similar or different physical-chemical or biological properties. The chapter focuses on the practical aspects of utilizing reversed-phase high-performance liquid chromatography (RPC) as a method for the purification and characterization of peptide hormone diastereoisomers. The reversed-phase packings containing bonded phases such as butyl, octyl, or diphenylsi-lanes are now commercially available, although there are not many examples in which these sorbents have been utilized for the separation of peptide diastereoisomers.
