Hybrid Liposomes Coupled to Steric Control with High Enantioselectivity

Article abstract of DOI:10.1021/jo00116a016

With respect to the hydrolysis of enantiomeric substrates (p-nitrophenyl N-dodecanoyl-D(L)-phenylalaninate; C12-D(L)-Phe-PNP) by the tripeptide catalyst (N-(benzyloxycarbonyl)-L-phenylalanyl-L-histidyl-L-leucine; Z-PheHisLeu), a remarkably high enantioselectivity (k^L_a/obsd/k^D_a/obsd = 28) along with marked rate-enhancement of the hydrolytic cleavage of C12-D(L)-Phe-PNP was obtained with specific coaggregates of 32 mol percent L-α-dipalmitoylphosphatidylcholine (DPPC) and 68 mol percent α-<4-(1,1,3,3-tetramethylbutyl)phenyl>-ω-hydroxypoly(oxy-1,2-ethanediyl) (TritonX-100).The enantioselectivity was maximized at the phase transition temperature (T_c) in the 65 mol percent DPPC/35 mol percent TritonX-100 and 32 mol percent DPPC/68 mol percent TritonX-100 coaggregate systems.The hydrophobicity and fluidity of the coaggregates can apparently be changed around T_c on the basis of isokinetic temperature and fluorescence parameter studies.