|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,900,000 (Direct Cost : ¥1,900,000)
This research project concerned the "footprint catalysis" study ; it was aimed its application to (1) enantioselective catalysis and (2) autocatalytic assymetric amplification. The footprint catalysis means an artificial catalytic antibody study, that is, a method for tailor-made catalyst design based on specific catalytic action of footprint cavities imprinted on a silica gel surface by the author's molecular imprinting with a proper template. Results : (1) The chirally imprinted footprint cavities using L-proline-hydantoin template showed highly enantioselective catalytic activities in nucleophilic cleavage of hydantoin rings of L-proline-, 5-methyl, and 5-phenyl-hydantoins. The cavities transformed L-isomers nearly 20 times effectively than D-isomers. An unique mechanism was proposed for these high enantioselectivities based on asymmetric face recognition of hydantoin rings.
(2) Footprint cavities imprinted with meso- (Z-Ala) _2NH catalized transacylation of LL,DD,and racemic isomers of (Z-Ala)_2O,respectively. In the catalysis, Z-L-alaninate, and Z-D-alaninate, one of the reaction product, stereoselectively showed competitive inhibition. It implied that cavities imprinted with meso- (Z-Ala) _2NH stereoselectively catalize meso- (Z-Ala) _2O under the presence of 2-D-alaninate to proceed transacylation of Z-D-alaninate, the latter of which promote the stereo-selective catalysis. Thus a potential autocatalytic asymmetric amplification was kinetically suggested to occur by the feed back mechanism.