ENANTIOSELECTIVE PERMEATION OF ALPHA-AMINO-ACID ISOMERS THROUGH POLY(AMINO ACID)-DERIVED MEMBRANES

Poly(L-glutamates) having amphiphilic side chains of (n-nonylphenoxy)oligo(oxyethylene) (NONx-PLG) were observed to possess potential properties as membrane materials for resolving optical isomers of a-amino acids. Permeation rate ratios of >8.0 for the d isomer to l isomer of tyrosine and tryptophan were achieved. Permeation of amino acids for times >500 h did not cause any drop in selectivity. Operating temperature considerably affected the permselectivity of the isomers. Since NONx-PLG adopted mainly an a-helical structure in its cast film and formed a liquid crystalline (nematic) type mesophase, this ordered structure of poly(amino acid) derivatives was considered to be the reason for the enantioselectivity of the membrane. © 1990, American Chemical Society. All rights reserved.