2639-63-6Relevant articles and documents
Solvent Configuration influences Enzyme Activity in Organic Media
Ottolina, Gianluca,Gianinetti, Francesca,Riva, Sergio,Carrea, Giacomo
, p. 535 - 536 (1994)
The activities of three hydrolases and one oxidoreductase have been found to be different when using (R)-carvone or (S)-carvone as the reaction medium indicating that solvent geometry can influence enzyme catalysis.
A chemically modified lipase preparation for catalyzing the transesterification reaction in even highly polar organic solvents
Solanki, Kusum,Gupta, Munishwar Nath
, p. 2934 - 2936 (2011)
Acylation of Pseudomonas cepacia lipase with Pyromellitic dianhydride to modify 72% of total amino groups was carried out. Different organic solvents were screened for precipitation of modified lipase. It was found that 1,2-dimethoxyethane was the best pr
Enzyme Access Tunnel Engineering in Baeyer-Villiger Monooxygenases to Improve Oxidative Stability and Biocatalyst Performance
Bornscheuer, Uwe,Kim, Myeong-Ju,Oh, Deok-Kun,Park, Jin-Byung,Park, Seongsoon,Park, So-Yeon,Seo, Eun-Ji
supporting information, (2021/11/10)
Hydrogen peroxide is involved in a variety of enzyme catalysis as an oxidant or toxic by-product. Thereby, attenuation of the H2O2-driven oxidative stress is one of the key issues for preparative biocatalysis. Here, a rational approach to improve the robustness of enzymes, in particular, Baeyer-Villiger monooxygenases (BVMOs) against H2O2 was investigated. The enzyme access tunnels, which may serve as exit paths for H2O2 from the active site to the bulk, were predicted by using the CAVER and/or protein energy landscape exploration (PELE) software for the phenylacetone monooxygenase variant (PAMO_C65D) from Thermobifida fusca and the BVMO from Pseudomonas putida KT2440. The amino acid residues, which are susceptible to oxidation by H2O2 (e. g., methionine and tyrosine) and located in vicinity of the predicted H2O2 migration paths, were substituted with less reactive or inert amino acids (e. g., leucine and isoleucine). This led to design of the H2O2-resistant enzyme variants, which became robust biocatalysts for synthetic applications. For instance, the H2O2-resistant P. putida BVMO reached turnover numbers of 4,100 for the BV oxygenation of 4-decanone, which is 2.8-fold greater than the parent enzyme. Moreover, the H2O2-resistant P. putida BVMO allowed 2-fold enhancement in titer of 9-(nonanoyloxy)nonanoic acid (8) formation in a cascade fatty acid biotransformation. Therefore, it was assumed that the CAVER/PELE-based H2O2 migration path engineering represents an efficient rational design approach to improve not only oxidative stability but also biotransformation performance of the H2O2-forming or utilizing enzymes (e. g., BVMOs, oxidases, and peroxidases). (Figure presented.).
Modulation of starch nanoparticle surface characteristics for the facile construction of recyclable Pickering interfacial enzymatic catalysis
Qi, Liang,Luo, Zhigang,Lu, Xuanxuan
, p. 2412 - 2427 (2019/05/17)
In this work, maize starch (MS) was successively modified via an esterification reaction with acetic anhydride (AA) and phthalic anhydride (PTA). Combined with the gelatinization-precipitation process, the formed starch nanoparticles at an AA/PTA ratio of 2 (MS-AP (2)) and 3 (MS-AP (3)) had similar regular spheres but distinct surface characteristics. In order to enhance the activity of lipase B from Candida antarctica (CALB) in an organic solvent, we designed an oil-in-water (o/w) and a water-in-oil (w/o) Pickering interfacial catalytic system simultaneously by utilizing MS-AP (2) and MS-AP (3) as robust Pickering emulsion stabilizers. Impressively, during the esterification of 1-butanol and vinyl acetate, the specific activity of CALB in the o/w (0.0843 U μL-1) or w/o (0.0724 U μL-1) Pickering interfacial catalytic system was much higher than that of free enzymes in the monophasic (0.0198 U μL-1) and biphasic (0.0282 U μL-1) system. Moreover, after preliminarily elaborating mass transfer discrepancies between the o/w and w/o Pickering interfacial catalytic systems and calculating their mass transfer resistance, we clarified the effects of the location of these two phases on the catalytic capacity of the Pickering emulsion. Impressively, both Pickering interfacial catalytic systems exhibited high effectiveness in product separation. It was found that the w/o Pickering emulsion enabled the organic product to be facilely isolated through a simple decantation, while the o/w Pickering emulsion achieved similar results after adjusting the system temperature. The bio-based nanomaterials and simple protocol, in conjunction with the stability to simultaneously achieve high catalysis efficiency and excellent recyclability, makes us believe that this starch nanoparticle-based Pickering interfacial catalytic system is a promising system for meeting the requirements of green and sustainable chemistry.
Graphite oxide as an efficient solid reagent for esterification reactions
Mirza-Aghayan, Maryam,Rahimifard, Mahshid,Boukherroub, Rabah
, p. 859 - 864 (2014/12/10)
Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.
