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Combination of oxyanion Gln114 mutation and medium engineering to influence the enantioselectivity of thermophilic lipase from Geobacillus zalihae.

Wahab RA, Basri M, Rahman MB, Rahman RN, Salleh AB, Leow TC - Int J Mol Sci (2012)

Bottom Line: The mutation improved enantioselectivity in Q114M over the wild-type, while enantioselectivity in Q114L was reduced.Molecular sieves employed as desiccant were found to adversely affect catalysis in the lipase variants, particularly in Q114M.The higher desiccant loading also increased viscosity in the reaction and further reduced the efficiency of the lipase-catalyzed esterifications.

View Article: PubMed Central - PubMed

Affiliation: Enzyme and Microbial Technology Group, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia; E-Mail: basya@science.upm.edu.my ; Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia.

ABSTRACT
The substitution of the oxyanion Q114 with Met and Leu was carried out to investigate the role of Q114 in imparting enantioselectivity on T1 lipase. The mutation improved enantioselectivity in Q114M over the wild-type, while enantioselectivity in Q114L was reduced. The enantioselectivity of the thermophilic lipases, T1, Q114L and Q114M correlated better with log p as compared to the dielectric constant and dipole moment of the solvents. Enzyme activity was good in solvents with log p < 3.5, with the exception of hexane which deviated substantially. Isooctane was found to be the best solvent for the esterification of (R,S)-ibuprofen with oleyl alcohol for lipases Q114M and Q114L, to afford E values of 53.7 and 12.2, respectively. Selectivity of T1 was highest in tetradecane with E value 49.2. Solvents with low log p reduced overall lipase activity and dimethyl sulfoxide (DMSO) completely inhibited the lipases. Ester conversions, however, were still low. Molecular sieves employed as desiccant were found to adversely affect catalysis in the lipase variants, particularly in Q114M. The higher desiccant loading also increased viscosity in the reaction and further reduced the efficiency of the lipase-catalyzed esterifications.

No MeSH data available.


Related in: MedlinePlus

The effects of various solvent properties on percentage conversion in the T1 lipase, Q114L and Q114M-catalyzed esterification of ibuprofen. The reactions of the lipase variants were carried out under similar conditions in solvents, dimethyl sulfoxide (DMSO), acetonitrile, ethyl acetate, hexane, isooctane, toluene, dodecane and N-tetradecane (8 mL), lyophilized lipase (5 mg) (R,S)-ibuprofen (0.8252 g, 4 mmole) and oleyl alcohol (1.872 mL, 6 mmole) at 50 °C and stirred at 200 rpm. The solvent properties investigated were (A) log p; (B) dielectric constant and (C) dipole moment.
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f1-ijms-13-11666: The effects of various solvent properties on percentage conversion in the T1 lipase, Q114L and Q114M-catalyzed esterification of ibuprofen. The reactions of the lipase variants were carried out under similar conditions in solvents, dimethyl sulfoxide (DMSO), acetonitrile, ethyl acetate, hexane, isooctane, toluene, dodecane and N-tetradecane (8 mL), lyophilized lipase (5 mg) (R,S)-ibuprofen (0.8252 g, 4 mmole) and oleyl alcohol (1.872 mL, 6 mmole) at 50 °C and stirred at 200 rpm. The solvent properties investigated were (A) log p; (B) dielectric constant and (C) dipole moment.

Mentions: The effect of different solvent properties on the esterification of racemic ibuprofen with oleyl alcohol catalyzed by T1, Q114L and Q114M were evaluated and the results are illustrated in Figure 1. The lipase activity in the esterification reaction was represented by the conversion of the ibuprofen ester. Activity in reactions of T1, Q114L and Q114M were found to be good when log p of solvents were 1.25 ≤ log p ≤ 7.6, but were inactivated in dimethyl sulfoxide (DMSO) (log p = −1.23). Their activity was noted when solvent dipole moment, μ < 10 or dielectric constant, ɛ < 0.1. The highest conversion catalyzed by T1, Q114L and Q114M occurred in isooctane which corresponded to 15.7%, 18.4% and 15.0%, respectively.


Combination of oxyanion Gln114 mutation and medium engineering to influence the enantioselectivity of thermophilic lipase from Geobacillus zalihae.

Wahab RA, Basri M, Rahman MB, Rahman RN, Salleh AB, Leow TC - Int J Mol Sci (2012)

The effects of various solvent properties on percentage conversion in the T1 lipase, Q114L and Q114M-catalyzed esterification of ibuprofen. The reactions of the lipase variants were carried out under similar conditions in solvents, dimethyl sulfoxide (DMSO), acetonitrile, ethyl acetate, hexane, isooctane, toluene, dodecane and N-tetradecane (8 mL), lyophilized lipase (5 mg) (R,S)-ibuprofen (0.8252 g, 4 mmole) and oleyl alcohol (1.872 mL, 6 mmole) at 50 °C and stirred at 200 rpm. The solvent properties investigated were (A) log p; (B) dielectric constant and (C) dipole moment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472768&req=5

f1-ijms-13-11666: The effects of various solvent properties on percentage conversion in the T1 lipase, Q114L and Q114M-catalyzed esterification of ibuprofen. The reactions of the lipase variants were carried out under similar conditions in solvents, dimethyl sulfoxide (DMSO), acetonitrile, ethyl acetate, hexane, isooctane, toluene, dodecane and N-tetradecane (8 mL), lyophilized lipase (5 mg) (R,S)-ibuprofen (0.8252 g, 4 mmole) and oleyl alcohol (1.872 mL, 6 mmole) at 50 °C and stirred at 200 rpm. The solvent properties investigated were (A) log p; (B) dielectric constant and (C) dipole moment.
Mentions: The effect of different solvent properties on the esterification of racemic ibuprofen with oleyl alcohol catalyzed by T1, Q114L and Q114M were evaluated and the results are illustrated in Figure 1. The lipase activity in the esterification reaction was represented by the conversion of the ibuprofen ester. Activity in reactions of T1, Q114L and Q114M were found to be good when log p of solvents were 1.25 ≤ log p ≤ 7.6, but were inactivated in dimethyl sulfoxide (DMSO) (log p = −1.23). Their activity was noted when solvent dipole moment, μ < 10 or dielectric constant, ɛ < 0.1. The highest conversion catalyzed by T1, Q114L and Q114M occurred in isooctane which corresponded to 15.7%, 18.4% and 15.0%, respectively.

Bottom Line: The mutation improved enantioselectivity in Q114M over the wild-type, while enantioselectivity in Q114L was reduced.Molecular sieves employed as desiccant were found to adversely affect catalysis in the lipase variants, particularly in Q114M.The higher desiccant loading also increased viscosity in the reaction and further reduced the efficiency of the lipase-catalyzed esterifications.

View Article: PubMed Central - PubMed

Affiliation: Enzyme and Microbial Technology Group, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia; E-Mail: basya@science.upm.edu.my ; Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia.

ABSTRACT
The substitution of the oxyanion Q114 with Met and Leu was carried out to investigate the role of Q114 in imparting enantioselectivity on T1 lipase. The mutation improved enantioselectivity in Q114M over the wild-type, while enantioselectivity in Q114L was reduced. The enantioselectivity of the thermophilic lipases, T1, Q114L and Q114M correlated better with log p as compared to the dielectric constant and dipole moment of the solvents. Enzyme activity was good in solvents with log p < 3.5, with the exception of hexane which deviated substantially. Isooctane was found to be the best solvent for the esterification of (R,S)-ibuprofen with oleyl alcohol for lipases Q114M and Q114L, to afford E values of 53.7 and 12.2, respectively. Selectivity of T1 was highest in tetradecane with E value 49.2. Solvents with low log p reduced overall lipase activity and dimethyl sulfoxide (DMSO) completely inhibited the lipases. Ester conversions, however, were still low. Molecular sieves employed as desiccant were found to adversely affect catalysis in the lipase variants, particularly in Q114M. The higher desiccant loading also increased viscosity in the reaction and further reduced the efficiency of the lipase-catalyzed esterifications.

No MeSH data available.


Related in: MedlinePlus