55019-71-1Relevant academic research and scientific papers
Efficient Assay for the Detection of Hydrogen Peroxide by Estimating Enzyme Promiscuous Activity in the Perhydrolysis Reaction
Wilk, Monika,Ostaszewski, Ryszard
, p. 1464 - 1469 (2021/02/01)
Hydrogen peroxide is an ideal oxidant in view of its availability, atom economy, or green aspects. Furthermore, it is produced by the cell mitochondria and plays a meaningful role in controlling physiological processes, but its unregulated production leads to the destruction of organs. Due to its diverse roles, a fast and selective method for hydrogen peroxide detection is the major limitation to preventing the negative effects caused by its excess. Therefore, we aimed to develop an efficient assay for the detection of H2O2. For this purpose, we combined the enzymatic method for the detection of hydrogen peroxide with the estimation of the promiscuity of various enzymes. We estimated the activity of an enzyme in the reaction of p-nitrophenyl esters with hydrogen peroxide resulting in the formation of peracid. To our knowledge, there is no example of a simple, multi-sensor demonstrating the promiscuous activity of an enzyme and detecting hydrogen peroxide in aqueous media.
Laboratory evolution of enantiocomplementary Candida antarctica lipase B mutants with broad substrate scope
Wu, Qi,Soni, Pankaj,Reetz, Manfred T.
supporting information, p. 1872 - 1881 (2013/08/24)
Candida antarctica lipase B (CALB) is a robust and easily expressed enzyme used widely in academic and industrial laboratories with many different kinds of applications. In fine chemicals production, examples include acylating kinetic resolution of racemic secondary alcohols and amines as well as desymmetrization of prochiral diols (or the reverse hydrolytic reactions). However, in the case of hydrolytic kinetic resolution of esters or esterifying kinetic resolution of acids in which chirality resides in the carboxylic acid part of the substrate, rate and stereoselectivity are generally poor. In the present study, directed evolution based on iterative saturation mutagenesis was applied to solve the latter problem. Mutants with highly improved activity and enantioselectivity relative to wild-type CALB were evolved for the hydrolytic kinetic resolution of p-nitrophenyl 2-phenylpropanoate, with the selectivity factor increasing from E = 1.2 (S) to E = 72 (S) or reverting to E = 42 (R) on an optional basis. Surprisingly, point mutations both in the acyl and alcohol pockets of CALB proved to be necessary. Some of the evolved CALB mutants are also efficient biocatalysts in the kinetic resolution of other chiral esters without performing new mutagenesis experiments. Another noteworthy result concerns the finding that enantiocomplementary CALB mutants for α-substituted carboxylic acid esters also show stereocomplementarity in the hydrolytic kinetic resolution of esters derived from chiral secondary alcohols. Insight into the source of stereoselectivity was gained by molecular dynamics simulations and docking experiments.
Comparison of deacylation rates of chymotryptic catalysis within an enantiomeric pair of p-nitrophenyl esters
Tanizawa,Yamada,Itoh,Kanaoka
, p. 2748 - 2749 (2007/10/02)
p-Nitrophenyl esters carrying a chiral acyl group were synthesized. These compounds were shown to meet the requirements of chymotrypsin for both the specific binding and the acylation. Therefore, the behavior of p-nitrophenyl esters with chymotrypsin is c
Enantioselectivity Effects in Hydrolytic Cleavage of Activated Substrates with α- and β-Cyclodextrins
Fornasier, Roberto,Reniero, Fabiano,Scrimin, Paolo,Tonellato, Umberto
, p. 193 - 196 (2007/10/02)
The kinetics of hydrolytic cleavage of the enantiomers of p- and m-nitrophenyl (Np) phenylacatate esters of general structure PhCR1R2-CO2-Np where R1,R2=H, Me , H, OMe , or CF3, OMe , and of the carbonates PhCHMe-OCO2-p-Np (7) and n-C6H13-CHMe-OCO2-p-Np (8), have been measured in the presence of α- and β-cyclodextrins.The rates of intracomplex cleavage were found to be larger for the R- than for the S-enantiomers in almost all cases; the enantioselectivity factors range from unity to ca. 19 depending on the relative size of the pairs of substituents R1 and R2.The effects have been interpreted with the help of molecular models.
