OPTICAL RESOLUTION OF PHENYLTHIOHYDANTOIN-AMINO ACIDS AND IDENTIFICATION OF PHENYLTHIOHYDANTOIN-D-AMINO ACID RESIDUE OF [D-ALA(2)]-METHIONINE ENKEPHALIN BY CAPILLARY ELECTROPHORESIS

We propose a system of protein sequence analysis with DL differentiati on using capillary electrophoresis (CE). This system consists of a pro tein sequencer and a CE. After fractionation of phenylthiohydantoin (P TH)-amino acids from the protein sequencer, optical resolution for eac h PTH-amino acid is performed by CE using some chiral selectors such a s digitonin, o-trimethyl-beta-cyclodextrin (TM-beta-CD) and others. In addition, optical resolution of all standard PTH-DL-amino acids inclu ding PTH-DL-carboxymethyl-Cys (CM-Cys) and cysteic acid (CYA) except f or PTH-DL-Lys was successfully developed. The resolution of PTH-DL-Lys could not be reconfirmed due to low reproducibility and the impuritie s. As a model peptide, [D-Ala(2)]-methionine enkephalin (L-Tyr-D-Ala-G ly-L-Phe-L-Met), was used and the sequence with DL differentiation was completely determined. (C) 1998 Elsevier Science B.V.