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Accession number;99A0228226
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| Title;Origin of the Enantioselectivity of Lipases. |
| Author;
EMA TADASHI
(Okayama Univ., Fac. of Eng.)
KOBAYASHI JUKA
(Okayama Univ., Fac. of Eng.)
MAENO SOICHI
(Okayama Univ., Fac. of Eng.)
SAKAI TAKASHI
(Okayama Univ., Fac. of Eng.)
UTAKA MASANORI
(Okayama Univ., Fac. of Eng.)
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Journal Title;Abstracts. Symposium on Biofunctional Chemistry
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Journal Code:L0836A
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ISSN:
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VOL.13th;NO.;PAGE.112-114(1998)
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| Figure&Table&Reference; |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;Kinetic measurements indicated that the ability of lipases to discriminate between the enantiomers in the transition state is high, while the ability to recognize the chirality of the substrates in the binding step is poor. The stereoelectronic considerations and the molecular modeling using an X-ray structure of Rhizomucor miehei lipase suggested that the lipase-catalyzed reactions proceed under the stereoelectronic control. This suggestion was supported by the semiempirical MO calculations carried out on the imidazole-catalyzed transesterification as a model reaction. The stereoelectronic effect operates in the transition state more effectively than in the tetrahedral intermediate. The stabilization energy due to the stereoelectronic effect operating in the transition state was estimated to be ca. 5kcal/mol. A transition-state model generally applicable to chiral secondary alcohols was invented. (author abst.) |
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