An α-acetoxy ketone reducing enzyme has been purified and characterized from the cell-free extract of bakers’ yeast (Saccharomyces cerevisiae). Only one NADPH-dependent dehydrogenase that catalyzed the reduction of α-acetoxy ketone was found in bakers’ yeast. The molecular weight of the enzyme was estimated to be 36 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme was composed of a single
Asymmetric reduction of ketones using recombinant E. coli cells that produce a versatile carbonyl reductase with high enantioselectivity and broad substrate specificity
The gene encoding a versatile biocatalyst that shows highenantioselectivity for a variety of ketones, SCR (Saccharomyces cerevisiae carbonyl reductase), has been identified, cloned, and expressed in Escherichia coli. Two types of expression systems with high NADPH-regenerating capacities have been constructed. One is the tandem system, where the genes encoding SCR and GDH (glucose dehydrogenase) are
编码,显示出对多种酮具有高对映选择性的通用基因的基因SCR(酿酒酵母羰基还原酶)已在大肠杆菌中鉴定,克隆和表达。已经构建了具有高NADPH再生能力的两种类型的表达系统。一个是串联系统,其中编码SCR和GDH(葡萄糖脱氢酶)的基因位于同一质粒中,另一个是双质粒系统,其中SCR和GDH的每个基因位于可以共存的单独质粒中在一个大肠杆菌细胞中 重组大肠杆菌不对称还原酮细胞产生合成有用的20种醇,其中11种对映体纯。这些产品之一的生产率高达41 g / L。
Iron-Catalyzed Dioxygenation of Alkenes and Terminal Alkynes by using (Diacetoxyiodo)benzene as Oxidant
作者:B. T. V. Srinivas、Vikas S. Rawat、Bojja Sreedhar
DOI:10.1002/adsc.201500681
日期:2015.11.16
syn-diacetoxylation of alkenes and 1,2-oxyacetoxylation of terminal alkynes has been developed using (diacetoxyiodo)benzene as oxidant. A broad range of internal and terminal alkenes, including electron-rich as well as electron-deficient alkenes, gave the desired products in good to excellent yields with high diastereoselectivity (up to >99:1 dr). In addition the high catalytic activity of ironcatalysis for the
BIOCATALYTIC ASYMMETRIC REDUCTION IN PREPARATION OF (S)-N-[5-(1,2-DIHYDROXY-ETHYL)-PYRAZINYL]-2,2-DIMETHYL-PROPIONAMIDE
申请人:Hanlon Steven Paul
公开号:US20080248537A1
公开(公告)日:2008-10-09
The present invention relates to biocatalytic asymmetric reduction for the preparation of 2-amino-[5-(1-hydroxy-2-hydroxy or halogen-ethyl)]-pyrazine derivatives of the formula
wherein R is lower alkylcarbonyl or an amino protecting group and R
1
is hydroxy or halogen. The compounds are key intermediates in the manufacture of a glucokinase activator.
diisopropyl fluorophosphate the undesirable hydrolysis of α-acetoxy ketones or alcohols was completely inhibited in the asymmetric reductionusingbakers’ yeast cell-free extract, but hardly inhibited in the reductionusing the whole cell suspension. The control of stereoselectivity by addition of metal chlorides was also conducted more effectively in the cell-free extract.