Systematic Investigation of <i>Saccharomyces </i><i>c</i><i>erevisiae</i> Enzymes Catalyzing Carbonyl Reductions
作者:Iwona A. Kaluzna、Tomoko Matsuda、Aileen K. Sewell、Jon D. Stewart
DOI:10.1021/ja0469479
日期:2004.10.1
each purified fusion protein. The stereoselectivities of beta-keto ester reductions depended both on the identity of the enzyme and the substrate structure, and some reductases yielded both L- and D-alcohols with high stereoselectivities. While alpha-keto esters were generally reduced with lower enantioselectivities, it was possible in all but one case to identify pairs of yeast reductases that delivered
Two NADPH-dependent α-keto ester reductases (Streptomyces thermocyaneoviolaceus keto ester reductase, STKER-II and -III) were purified from S. thermocyaneoviolaceus IFO 14271, one of thermophilic actinomycetes. The molecular masses of native STKER-II and -III were estimated to be 60 kDa and 70 kDa by gel filtration chromatography, respectively. These enzymes were both homodimers, with 29-kDa and 30-kDa subunit molecular masses based on SDS polyacrylamide gel electrophoresis. STKER-II and -III were stable from pH 7.0 to 10.0 and pH 5.5 to 9.0, respectively. Ethyl 3-methyl-2-oxobutanoate was reduced by both enzymes isolated to the corresponding (R)-hydroxy ester with excellent enantiomeric excess. STKER-III showed high stereoselectivity for the reduction of bulky substrates, while the selectivity of the STKER-II-catalyzed reduction was low except for ethyl 3-methyl-2-hydroxybutanoate. Both enzymes had small Km values toward aliphatic keto esters having a long alkyl chain.
A thermoregulated phase-separable chiral Pt nanocatalyst for recyclable asymmetric hydrogenation of α-ketoesters
作者:Xiuru Xue、Yanhua Wang、Fu-She Han
DOI:10.1039/c7cc00892a
日期:——
Asymmetric hydrogenation of α-ketoesters catalyzed by a recyclable chiral Pt nanocatalyst system possessing thermoregulated phase-separation property is presented.
α-酮酸酯的不对称氢化反应由可回收的手性铂纳米催化剂系统催化,具有热调节相分离性能。
METHOD FOR PRODUCING OPTICALLY ACTIVE 2-HYDROXY ESTER AND NOVEL INTERMEDIATE COMPOUND
申请人:Shiina Isamu
公开号:US20110319650A1
公开(公告)日:2011-12-29
Disclosed is a method for producing an optically active 2-hydroxy ester, comprising selectively esterifying one enantiomer of a racemic 2-hydroxy ester in a solvent containing a catalyst such as tetramisole or benzotetramisole, and a carboxylic acid anhydride, or a carboxylic acid anhydride and a carboxylic acid. In particular, in the case where the solvent contains a carboxylic acid anhydride, but does not contain a carboxylic acid, as the carboxylic acid anhydride, a carboxylic acid anhydride containing a tertiary or quaternary carbon atom in the a-position is used. On the other hand, in the case where the solvent contains a carboxylic acid anhydride and a carboxylic acid, as the carboxylic acid, a carboxylic acid containing a tertiary or quaternary carbon atom in the a-position is used.
Kinetic Resolution of the Racemic 2-Hydroxyalkanoates Using the Enantioselective Mixed-Anhydride Method with Pivalic Anhydride and a Chiral Acyl-Transfer Catalyst
A variety of opticallyactive 2‐hydroxyalkanoates and the corresponding 2‐acyloxyalkanoates are produced by the kinetic resolution of racemic 2‐hydroxyalkanoates by using achiral 2,2‐diarylacetic acid with hindered carboxylicanhydrides as the coupling reagents. The combined use of diphenylacetic acid, pivalic anhydride, and (+)‐(R)‐benzotetramisole ((R)‐BTM) effectively produces (S)‐2‐hydroxyalkanoates