ABSTRACT
Since most of the proteinogenic alpha-amino acids contain a chiral carbon atom, the stereoisomers of both these amino acids and the peptides in which they are to be found may possess differences in biological activity in living systems. The important analytical task of the separation of optical isomers is achieved mainly by chromatographic methods. This special review surveys direct and indirect HPLC separations of biologically important, small epimeric peptides and their L, D-amino acid content.
Subject(s)
Amino Acids , Chromatography, High Pressure Liquid/methods , Peptides/chemistry , Peptides/isolation & purification , Amino Acid Sequence , Animals , Biological Products/chemistry , Biological Products/metabolism , Humans , Peptides/chemical synthesis , Peptides/metabolism , StereoisomerismABSTRACT
Two novel natural derivatives (2 and 3) of the ergot alkaloid alpha-ergokryptine (1), as well as their synthetically brominated analogues (5 and 6) were isolated and identified by NMR and MS methods. Compounds 2 and 5 contain what appears to be a so far unknown natural amino acid building block. Complete 1H and 13C NMR assignments are given for compounds 1-6.
