title: Ability of different biomaterials to enantioselectively catalyze oxidation and reduction reactions.
abstract: We studied the ability of different biomaterials to enantioselectively catalyze oxidation or reduction reactions with the help of substrate rac-1-m or p-ArCH(OH)Me and the 1-o-ArC(O)Me derivatives. Apoenzyme (NAD(P)(+)-dependent secondary alcohol dehydrogenase(NAD(P)-E)) and cofactor (NAD(P)(+)) were activated by preincubating immobilized aqueous plant leaf (e.g., young wheat leaves), cereal tissue (wheat bran), vegetable (e.g., carrot), and seaweed (e.g., wakame seaweed) solutions, and the NAD(P)-E oxidized only (R)-isomers highly enantioselectively. Thus, greater than 99% ee(s) of (S)-isomers (1m-5m and 1p-5p) can be obtained from corresponding rac-1-m or p-ArCH(OH)Me. Further, immobilized chlorella cells and immobilized baker's yeast can reduce highly stereoselectively; greater than 99% ee(s) of (S)-isomers (1o-5o) can be obtained from corresponding 1-o-ArC(O)Me. Specific use of each isomer ((S)-6 and (R)-6) with greater than 99% ee(s) of racemic-1-2-NpCH(OH)Me becomes possible through selective use of NAD(P)-E eluted from artemisia vulgaris indica leaves and young wheat leaves. We suggest that the pH of the reaction media can determine not only the direction of NAD(P)-E, toward enantioselectively catalyzed oxidation (pH > 7.0) or reduction reaction (pH < 7.0), but also the regioselective reactivity of NAD(P)-E to the substrate o- (pH < 7.0), m-, and p-substituted groups (pH > 7.0). Thus, in comparison to current biocatalysts, several biomaterials can serve as asymmetric reagent bases, providing easily obtained, low-cost natural catalysts with stereoselectivity, regioselectivity, and substrate specificity that work under mild conditions for asymmetric synthesis of organic compounds.
authors.affiliation: Sanyo Shokuhin Co., Ltd., R & D, 555-4 Asakura, Maebashi, Gunma 371-0811, Japan. nagaoka1@sea.plala.or.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nagaoka
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis*; D019306:Artemisia / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D002384:Catalysis; D001467:Hordeum / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D008422:Materials Testing; D009249:NADP / Q000737:chemistry*; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D011208:Powders; D013379:Substrate Specificity; D014908:Triticum / Q000737:chemistry*
chemical_list: D000438:Alcohols; D001672:Biocompatible Materials; D010936:Plant Extracts; D011208:Powders; D009249:NADP