61597-99-7

Upstream product

• 591-60-6 butyl acetoacetate 

Relevant academic research and scientific papers

Single-Point Mutant Inverts the Stereoselectivity of a Carbonyl Reductase toward β-Ketoesters with Enhanced Activity

Enzyme stereoselectivity control is still a major challenge. To gain insight into the molecular basis of enzyme stereo-recognition and expand the source of antiPrelog carbonyl reductase toward β-ketoesters, rational enzyme design aiming at stereoselectivity inversion was performed. The designed variant Q139G switched the enzyme stereoselectivity toward β-ketoesters from Prelog to antiPrelog, providing corresponding alcohols in high enantiomeric purity (89.1–99.1 % ee). More importantly, the well-known trade-off between stereoselectivity and activity was not found. Q139G exhibited higher catalytic activity than the wildtype enzyme, the enhancement of the catalytic efficiency (kcat/Km) varied from 1.1- to 27.1-fold. Interestingly, the mutant Q139G did not lead to reversed stereoselectivity toward aromatic ketones. Analysis of enzyme–substrate complexes showed that the structural flexibility of β-ketoesters and a newly formed cave together facilitated the formation of the antiPrelog-preferred conformation. In contrast, the relatively large and rigid structure of the aromatic ketones prevents them from forming the antiPrelog-preferred conformation.

Asymmetric visible-light photobiocatalytic reduction of β-keto esters utilizing the cofactor recycling system in Synechocystis sp. PCC 6803

The asymmetric reduction of β-keto esters employing a wild-type strain of cyanobacterium Synechocystis sp. PCC 6803 under illumination of red LED light at 25 °C for 24 h was evaluated. As a result, the corresponding (R)-β-hydroxy esters were obtained as major products. The R-selectivity was shown to increase for bulkier substrates. Moreover, it was also found that the R-selectivity increased with decreasing substrate concentrations. This can be explained by the assumption that the Km value of the R-selective reductase is smaller than that of the S-selective enzyme involved in the reaction. Additionally, it was demonstrated that the R-selective reductase required the light-dependent production of reduced nicotinamide adenine dinucleotide phosphate (NADPH) for effective reaction; however, the S-selective variant did not. Overall, cyanobacterium was employed as a sustainable photobiocatalyst proliferating under illumination of light, while utilizing inorganic salts and atmospheric carbon dioxide (CO2). Employing the whole-cell system allowed for the preparation of industrially-important chiral compounds, such as optically active β-hydroxy esters.

Asymmetric Reduction of Functionalized Ketones with a Sodium Borohydride-(L)-Tartaric Acid System

The sodium borohydride-(L)-tartaric acid system is effective for the asymmetric reduction of prochiral ketones if they are functionalized on the α- or β-carbon with a group that can chelate to the chirally modified borohydride.

ENHANCED OPTICAL PURITY OF 3-HYDROXYESTERS OBTAINED BY BAKER'S YEAST REDUCTION OF 3-KETOESTERS

Fermenting Baker's yeast, enclosed in a dialysis tube, reduces efficiently 3-ketoesters added to the surrounding subtonic solution, to the corresponding 3-hydroxyesters in good yield (45-55percent) and enhanced optical purity (ee 96-97percent)