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Sorour Hassani - One of the best experts on this subject based on the ideXlab platform.

  • Catalytic Efficiency and thermostability improvement of suc2 invertase through rational site directed mutagenesis
    Enzyme and Microbial Technology, 2017
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility<5% were selected through multiple-sequence alignments, molecular modelling, structural and computational analyses. Consequently, SInv and 5 mutants including three mutants with single point substitution [Mut1=P152V, Mut2=S85V and Mut3=K153F)], one mutant with two points [Mut4=S305V-N463V] and one mutant with three points [Mut5=S85V-K153F-T271V] were developed via site-directed mutagenesis and produced using Pichia pastoris as the host. Physicochemical studies on these enzymes indicated that the selected amino acids which were located in the active site region mainly influenced Catalytic Efficiency. The best improvement belonged to Mut1 (54% increase in Kcat/Km) and Mut3 exhibited the worst effect (90% increase in Km). These results suggest that Pro152 and Lys153 play key role in preparation of the right substrate lodging in the active site of SInv. The best thermostability improvement (16%) was observed for Mut4 in which two hydrophilic residues located on the loops, far from the active site, were replaced by Valines. These results suggest that tactful simultaneous substitution of influential hydrophilic residues in both active site region and peripheral loops with hydrophobic amino acids could result in more thermostable invertases with enhanced Catalytic Efficiency.

  • Catalytic Efficiency and thermostability improvement of Suc2 invertase through rational site-directed mutagenesis
    Enzyme and microbial technology, 2016
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility

Nooshin Mohandesi - One of the best experts on this subject based on the ideXlab platform.

  • Catalytic Efficiency and thermostability improvement of suc2 invertase through rational site directed mutagenesis
    Enzyme and Microbial Technology, 2017
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility<5% were selected through multiple-sequence alignments, molecular modelling, structural and computational analyses. Consequently, SInv and 5 mutants including three mutants with single point substitution [Mut1=P152V, Mut2=S85V and Mut3=K153F)], one mutant with two points [Mut4=S305V-N463V] and one mutant with three points [Mut5=S85V-K153F-T271V] were developed via site-directed mutagenesis and produced using Pichia pastoris as the host. Physicochemical studies on these enzymes indicated that the selected amino acids which were located in the active site region mainly influenced Catalytic Efficiency. The best improvement belonged to Mut1 (54% increase in Kcat/Km) and Mut3 exhibited the worst effect (90% increase in Km). These results suggest that Pro152 and Lys153 play key role in preparation of the right substrate lodging in the active site of SInv. The best thermostability improvement (16%) was observed for Mut4 in which two hydrophilic residues located on the loops, far from the active site, were replaced by Valines. These results suggest that tactful simultaneous substitution of influential hydrophilic residues in both active site region and peripheral loops with hydrophobic amino acids could result in more thermostable invertases with enhanced Catalytic Efficiency.

  • Catalytic Efficiency and thermostability improvement of Suc2 invertase through rational site-directed mutagenesis
    Enzyme and microbial technology, 2016
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility

Vo Thu An Nguyen - One of the best experts on this subject based on the ideXlab platform.

  • upward trend in Catalytic Efficiency of rare earth triflate catalysts in friedel crafts aromatic sulfonylation reactions
    Asian Journal of Organic Chemistry, 2014
    Co-Authors: Vo Thu An Nguyen, Fritz Duus
    Abstract:

    A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The Catalytic Efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in Catalytic Efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water-exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well-known discontinuity in lanthanide properties.

  • Upward Trend in Catalytic Efficiency of Rare‐Earth Triflate Catalysts in Friedel–Crafts Aromatic Sulfonylation Reactions
    Asian Journal of Organic Chemistry, 2014
    Co-Authors: Vo Thu An Nguyen, Fritz Duus
    Abstract:

    A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The Catalytic Efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in Catalytic Efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water-exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well-known discontinuity in lanthanide properties.

Fritz Duus - One of the best experts on this subject based on the ideXlab platform.

  • upward trend in Catalytic Efficiency of rare earth triflate catalysts in friedel crafts aromatic sulfonylation reactions
    Asian Journal of Organic Chemistry, 2014
    Co-Authors: Vo Thu An Nguyen, Fritz Duus
    Abstract:

    A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The Catalytic Efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in Catalytic Efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water-exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well-known discontinuity in lanthanide properties.

  • Upward Trend in Catalytic Efficiency of Rare‐Earth Triflate Catalysts in Friedel–Crafts Aromatic Sulfonylation Reactions
    Asian Journal of Organic Chemistry, 2014
    Co-Authors: Vo Thu An Nguyen, Fritz Duus
    Abstract:

    A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The Catalytic Efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in Catalytic Efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water-exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well-known discontinuity in lanthanide properties.

Kamahldin Haghbeen - One of the best experts on this subject based on the ideXlab platform.

  • Catalytic Efficiency and thermostability improvement of suc2 invertase through rational site directed mutagenesis
    Enzyme and Microbial Technology, 2017
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility<5% were selected through multiple-sequence alignments, molecular modelling, structural and computational analyses. Consequently, SInv and 5 mutants including three mutants with single point substitution [Mut1=P152V, Mut2=S85V and Mut3=K153F)], one mutant with two points [Mut4=S305V-N463V] and one mutant with three points [Mut5=S85V-K153F-T271V] were developed via site-directed mutagenesis and produced using Pichia pastoris as the host. Physicochemical studies on these enzymes indicated that the selected amino acids which were located in the active site region mainly influenced Catalytic Efficiency. The best improvement belonged to Mut1 (54% increase in Kcat/Km) and Mut3 exhibited the worst effect (90% increase in Km). These results suggest that Pro152 and Lys153 play key role in preparation of the right substrate lodging in the active site of SInv. The best thermostability improvement (16%) was observed for Mut4 in which two hydrophilic residues located on the loops, far from the active site, were replaced by Valines. These results suggest that tactful simultaneous substitution of influential hydrophilic residues in both active site region and peripheral loops with hydrophobic amino acids could result in more thermostable invertases with enhanced Catalytic Efficiency.

  • Catalytic Efficiency and thermostability improvement of Suc2 invertase through rational site-directed mutagenesis
    Enzyme and microbial technology, 2016
    Co-Authors: Nooshin Mohandesi, Kamahldin Haghbeen, Omid Ranaei, Seyed Shahriar Arab, Sorour Hassani
    Abstract:

    Engineering of invertases has come to attention because of increasing demand for possible applications of invertases in various industrial processes. Due to the known physicochemical properties, invertases from micro-organisms such as Saccharomyces cerevisiae carrying SUC2 gene are considered as primary models. To improve thermostability and Catalytic Efficiency of SUC2 invertase (SInv), six influential residues with Relative Solvent Accessibility