Studies on thermodynamics for the hydrolysis. II. The temperature effect on the stereoselective deacylation of amino acid esters in bilayer and micellar systems.

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概要

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• Stereoselective deacylations of <I>p</I>-nitrophenyl <I>N</I>-acyl-D(or L)-phenylalaninates(D(or L)-S<I><SUB>n</SUB></I>; <I>n</I>=2, 12, and 16) and <I>N</I>-benzyloxycarbonyl-D(L)-phenylalaninates(D(L)-ZS) by the bilayer and micellar catalytic systems of L-histidine derivatives (LauHis, MyrHis, PalHis, LauHisLeu, and MyrHisLeu) and surfactants (2C<I><SUB>m</SUB></I>N2C<SUB>1</SUB>Br with <I>m</I>=12, 14, and 16, CTAB, OTAC, and (<I>R</I>)-(+)-SUR<SUB>16</SUB>) were performed. It is noteworthy that the temperature dependence of enantioselectivity for the deacylation of S<SUB>12</SUB> having a long acyl chain is bell-shaped with maxima at 25 °C and 15–25 °C in the bilayer systems of MyrHis+2C<SUB>12</SUB>N2C<SUB>1</SUB>Br and MyrHisLeu+2C<SUB>12</SUB>N2C<SUB>1</SUB>Br, respectively. On the other hand, the enantioselectivity for the S<SUB>12</SUB> deacylation catalyzed by LauHisLeu in the presence of the CTAB micelles increases as temperature is lowered (the highest enantiomer rate ratio (<I>k</I><SUP>L</SUP><SUB>a,obsd</SUB>⁄<I>k</I><SUP>D</SUP><SUB>a,obsd</SUB>=12) is attained at 20 °C). The enantioselectivity for the deacylation of S<SUB>2</SUB> having a short acyl chain, however, is almost constant and considerably lowered in comparison with that for the deacylation of S<SUB>12</SUB> in both the bilayer and micellar systems. According to the isokinetic temperature (β), the deacylation of S<I><SUB>n</SUB></I> (<I>n</I>=2 and 12) and ZS in the bilayer systems might be entropy-driven, whereas that in the micellar systems might be enthalpy-driven. The stronger hydrophobic microenvironment of the bilayer systems in the ester-deacylation would probably be connected with the entropy-driven nature.

• 公益社団法人 日本化学会の論文

著者

• UEOKA Ryuichi

  Department of Applied Life Science, Sojo University

• Matsumoto Y\={o}ko

  Department of Industrial Chemistry, Kumamoto Institute of Technology

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• Phase Behavior of a Lipid Bilayer System Studied by a Replica-Exchange Molecular Dynamics Simulation
• The stereoselective deacylation of long-chain amino acid esters by comicelles of N-acyl-L-histidine and various cationic surfactants.
• Studies on thermodynamics for the hydrolysis. II. The temperature effect on the stereoselective deacylation of amino acid esters in bilayer and micellar systems.
• The micelle-promoted selective hydrolysis of anionic and nonionic ester substrates by hydroxamic acids and histidine derivatives.

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