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Zarevúcká, Marie; Vacek, Miroslav; Wimmer, Zdeněk; Brunet, Christine; Legoy, Marie‐Dominique

doi:10.1023/a:1005539626471

Cited by 11 publications

(1 citation statement)

References 16 publications

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“…For reverse hydrolysis, according to the thermodynamic principles, the reaction equilibrium can be shifted toward formation of glycosidic bonds either by increasing substrate concentrations, decreasing the water activity, or by the combination of both (De Winter et al 2013;Monsan and Paul 1995;Panintrarux et al 1995;Vic et al 1997). Therefore, enzymatic glycosylation via reverse hydrolysis is commonly optimized by using organic solvents, addition of high reactant concentrations, increasing the reaction temperature to 40-60°C (van Rantwijk et al 1999), or employing microwave irradiation (Zarevúcka et al 1999). However, addition of organic solvents in the reaction solution usually inactivates the glycosidases (Trani et al 2004;Vic et al 1997).…”

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confidence: 99%

Site-directed mutagenesis of α-l-rhamnosidase from Alternaria sp. L1 to enhance synthesis yield of reverse hydrolysis based on rational design

Liu

Yin³

et al. 2016

Appl Microbiol Biotechnol

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The α-L-rhamnosidase catalyzes the hydrolytic release of rhamnose from polysaccharides and glycosides and is widely used due to its applications in a variety of industrial processes. Our previous work reported that a wild-type α-L-rhamnosidase (RhaL1) from Alternaria sp. L1 could synthesize rhamnose-containing chemicals (RCCs) though reverse hydrolysis reaction with inexpensive rhamnose as glycosyl donor. To enhance the yield of reverse hydrolysis reaction and to determine the amino acid residues essential for the catalytic activity of RhaL1, site-directed mutagenesis of 11 residues was performed in this study. Through rationally designed mutations, the critical amino acid residues which may form direct or solvent-mediated hydrogen bonds with donor rhamnose (Asp, Asp, Asp, Glu, Arg, His, and Trp) and may form the hydrophobic pocket in stabilizing donor (Trp, Tyr, Tyr, and Trp) in active-site of RhaL1 were analyzed, and three positive mutants (W261Y, Y302F, and Y316F) with improved product yield stood out. From the three positive variants, mutant W261Y accelerated the reverse hydrolysis with a prominent increase (43.7 %) in relative yield compared to the wild-type enzyme. Based on the 3D structural modeling, we supposed that the improved yield of mutant W261Y is due to the adjustment of the spatial position of the putative catalytic acid residue Asp. Mutant W261Y also exhibited a shift in the pH-activity profile in hydrolysis reaction, indicating that introducing of a polar residue in the active site cavity may affect the catalysis behavior of the enzyme.

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confidence: 99%

Site-directed mutagenesis of α-l-rhamnosidase from Alternaria sp. L1 to enhance synthesis yield of reverse hydrolysis based on rational design

Liu

Yin³

et al. 2016

Appl Microbiol Biotechnol

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Microwave‐Assisted Chemical Reactions

Nüchter

Müller

Ondruschka³

et al. 2003

Chem Eng & Technol

141

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This article reviews the state of the art of microwave-assisted reactions and the influence of microwaves on mass and heat transfer. The heating behavior of representative test reactions and single substances is compared for heating with microwaves and thermal energy. Similarities and differences between convective heating and dielectric irradiation methods are discussed with regard to the yield, the selectivity, and the enantiomeric purity of the reaction products. Furthermore, prevailing problems related to the scale-up of microwave-assisted reactions are discussed considering the energy absorption of the substances and mixtures to be heated, and their dependence on the energy consumption and the amount of substance.

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Lang¹,

Trowitzsch‐Kienast²

2002

Biotenside

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Cited by 11 publications

References 16 publications

Site-directed mutagenesis of α-l-rhamnosidase from Alternaria sp. L1 to enhance synthesis yield of reverse hydrolysis based on rational design

Site-directed mutagenesis of α-l-rhamnosidase from Alternaria sp. L1 to enhance synthesis yield of reverse hydrolysis based on rational design

Microwave‐Assisted Chemical Reactions

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