CHROMATOGRAPHIC BEHAVIOR OF OPIOID-PEPTIDES CONTAINING BETA-METHYLPHENYLALANINE ISOMERS

A reversed-phase high-performance liquid chromatographic (RP-HPLC) met hod was developed to obtain pure erythro[2S3S, 2R3R]- and threo[2S3R, 2R3S]-beta-methylphenylalanine. These amino acids were incorporated in to an enkephalin, H-Tyr-D-Ala-Gly-beta-MePhe-Val-Val-Gly-NH2, and into a deltorphin C, H-Tyr-D-Ala-beta-MePhe-Asp-Val-Val-Gly-NH2, analogue, which yielded four diastereoisomers of the peptides. The diastereoiso mers were separated on different columns and with different eluent sys tems. The sequence of elution of the peptide diastereoisomers was dete rmined after hydrolysis of the peptides. For identification of the bet a-methylphenylalanine enantiomers, enzymatic degradation and an RP-HPL C method were used, with application of 1-fluoro-2,4-dinitrophenyl-5-L -alanine amide as derivatizing reagent.