NOVEL STEREOSELECTIVE INCORPORATION AND HYDROLYSIS OF LONG-CHAIN AMINO-ACID SUBSTRATES BY VESICULAR MEMBRANE SYSTEMS WHICH INCLUDE TRI-PEPTIDE OR TETRA-PEPTIDE CATALYSTS

In the vesicular membrane systems comprising N,N-didodecyl-N,N-dimethy lammonium bromide and tri- or tetra-peptide catalysts (pH 7.68; ionic strength mu = 0.15; 298 K), Z-L-Leu-L-His-L-Leu (or Z-L-Leu-L-His-L-Le u-L-Leu), having a hydrophobic terminal L-leucine (or L-leucyl-L-leuci ne) unit, contributed to the stereoselective binding of long-chain p-n itrophenyl N-hexadecanoyl-L (and D)-phenyalanates with the remarkably high binding ratio K-b(L/D) = 11 (or 7.3) and overall stereoselectivit y [k(cat)(L/D) = 35 (or 8.1)].