SEPARATION OF ENANTIOMERIC BETA-METHYL AMINO-ACIDS AND OF BETA-METHYLAMINO-ACID CONTAINING PEPTIDES

Erythro-D,L- and threo-D,L-beta-methylphenylalanine, -beta-methyltyros ine and methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid were s ynthesized. High-performance liquid chromatographic methods were devel oped for the separation and identification of the enantiomers of the b eta-methyl amino acids, with the application of 1-fluoro-2,4-dinitroph enyl-5-L-alanine amide and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosy l isothiocyanate as derivatizing reagents. These amino acids were inco rporated into the mu-agonist/delta-antagonist opioid peptides H-beta-M eTyr-Tic-Phe-Phe-NH2, H-Tyr-Tic-beta-MePhe-Phe-NH2 and H-Tyr-Tic-Phe-b eta-MePhe-NH2, and the delta-antagonist H-Tyr-beta-MeTic-Phe-Phe-OH, b y solid-phase peptide synthesis. Each peptide has four stereoisomers. The peptide stereoisomers were separated on different columns and in d ifferent eluent systems and the elution order of the peptide epimers w as determined.