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Robert A. Kanaly - One of the best experts on this subject based on the ideXlab platform.

  • production of natural fragrance aromatic acids by coexpression of trans anethole oxygenase and p anisaldehyde dehydrogenase genes of pseudomonas putida jyr 1 in escherichia coli
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Somwang Kurusarttra, Robert A. Kanaly
    Abstract:

    A gene encoding p-anisaldehyde dehydrogenase (PAADH), which catalyzes the oxidation of p-anisaldehyde to p-anisic acid, was identified to be clustered with the trans-anethole oxygenase (tao) gene in Pseudomonas putida JYR-1. Heterologously expressed PAADH in Escherichia coli catalyzed the oxidation of vanillin, veratraldehyde, and piperonal to the corresponding aromatic acids vanillic acid, veratric acid, and piperonylic acid, respectively. Coexpression of trans-anethole oxygenase (TAO) and PAADH in E. coli also resulted in the successful transformation of trans-anethole, isoeugenol, O-methyl isoeugenol, and Isosafrole to p-anisic acid, vanillic acid, veratric acid, and piperonylic acid, respectively, which are compounds found in plants as secondary metabolites. Because of the relaxed substrate specificity and high transformation rates by coexpressed TAO and PAADH in E. coli, the engineered strain has potential to be applied in the fragrance industry.

  • isolation of a gene responsible for the oxidation of trans anethole to para anisaldehyde by pseudomonas putida jyr 1 and its expression in escherichia coli
    Applied and Environmental Microbiology, 2012
    Co-Authors: Robert A. Kanaly
    Abstract:

    ABSTRACT A plasmid, pTA163, in Escherichia coli contained an approximately 34-kb gene fragment from Pseudomonas putida JYR-1 that included the genes responsible for the metabolism of trans -anethole to protocatechuic acid. Three Tn 5 -disrupted open reading frame 10 (ORF 10) mutants of plasmid pTA163 lost their abilities to catalyze trans -anethole. Heterologously expressed ORF 10 (1,047 nucleotides [nt]) under a T7 promoter in E. coli catalyzed oxidative cleavage of a propenyl group of trans -anethole to an aldehyde group, resulting in the production of para -anisaldehyde, and this gene was designated tao ( t rans -anethole oxygenase). The deduced amino acid sequence of TAO had the highest identity (34%) to a hypothetical protein of Agrobacterium vitis S4 and likely contained a flavin-binding site. Preferred incorporation of an oxygen molecule from water into p -anisaldehyde using 18 O-labeling experiments indicated stereo preference of TAO for hydrolysis of the epoxide group. Interestingly, unlike the narrow substrate range of isoeugenol monooxygenase from Pseudomonas putida IE27 and Pseudomonas nitroreducens Jin1, TAO from P. putida JYR-1 catalyzed isoeugenol, O -methyl isoeugenol, and Isosafrole, all of which contain the 2-propenyl functional group on the aromatic ring structure. Addition of NAD(P)H to the ultrafiltered cell extracts of E. coli (pTA163) increased the activity of TAO. Due to the relaxed substrate range of TAO, it may be utilized for the production of various fragrance compounds from plant phenylpropanoids in the future.

Hor-gil Hur - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of a Self-sufficient Trans-Anethole Oxygenase from Pseudomonas putida JYR-1
    PLoS ONE, 2013
    Co-Authors: Dongfei Han, Michael J. Sadowsky, Youhoon Chong, Hor-gil Hur
    Abstract:

    A novel flavoprotein monooxygenase, trans-anethole oxygenase (TAO), from Pseudomonas putida JYR-1, which is capable of catalyzing the oxidation of trans-anethole to p-anisaldehyde, was heterologously expressed in E. coli and purified. Enzymatic kinetics of diverse substrates and cofactors revealed that TAO is likely to be a novel self-sufficient flavoprotein monooxygenase. Enzyme assays of GST-TAO demonstrated that TAO catalyzed a trans-anethole oxidation reaction without auxiliary component enzyme-like electron-transfer flavin reductases. The single component TAO had the ability to reduce flavin cofactors and simultaneously oxidize trans-anthole to p-anisaldehyde. In the processes of reduction of flavin and oxidation of trans-anethole, TAO accepted various flavin and NAD(P)H cofactors. TAO also catalyzed oxidation of isoeugenol, O-methyl isoeugenol, and Isosafrole, all of which contain the 2-propenyl functional group on the aromatic ring structure with different catalytic efficiency. TAO had the greatest catalytic efficiency (kcat/Km) with the original substrate, trans-anethole. Investigation about partially deleted mutants of TAO indicated that reductase active sites appeared to be located near the N terminal. Site directed mutagenesis studies also proved that the proposed flavin binding sites, Trp-38, Thr-43, Tyr-55, were critical for flavin reduction. However, disruption of any portion of TAO eliminated the oxygenase activity.

Dongfei Han - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of a Self-sufficient Trans-Anethole Oxygenase from Pseudomonas putida JYR-1
    PLoS ONE, 2013
    Co-Authors: Dongfei Han, Michael J. Sadowsky, Youhoon Chong, Hor-gil Hur
    Abstract:

    A novel flavoprotein monooxygenase, trans-anethole oxygenase (TAO), from Pseudomonas putida JYR-1, which is capable of catalyzing the oxidation of trans-anethole to p-anisaldehyde, was heterologously expressed in E. coli and purified. Enzymatic kinetics of diverse substrates and cofactors revealed that TAO is likely to be a novel self-sufficient flavoprotein monooxygenase. Enzyme assays of GST-TAO demonstrated that TAO catalyzed a trans-anethole oxidation reaction without auxiliary component enzyme-like electron-transfer flavin reductases. The single component TAO had the ability to reduce flavin cofactors and simultaneously oxidize trans-anthole to p-anisaldehyde. In the processes of reduction of flavin and oxidation of trans-anethole, TAO accepted various flavin and NAD(P)H cofactors. TAO also catalyzed oxidation of isoeugenol, O-methyl isoeugenol, and Isosafrole, all of which contain the 2-propenyl functional group on the aromatic ring structure with different catalytic efficiency. TAO had the greatest catalytic efficiency (kcat/Km) with the original substrate, trans-anethole. Investigation about partially deleted mutants of TAO indicated that reductase active sites appeared to be located near the N terminal. Site directed mutagenesis studies also proved that the proposed flavin binding sites, Trp-38, Thr-43, Tyr-55, were critical for flavin reduction. However, disruption of any portion of TAO eliminated the oxygenase activity.

Somwang Kurusarttra - One of the best experts on this subject based on the ideXlab platform.

J F C Boodts - One of the best experts on this subject based on the ideXlab platform.

  • solvent and support electrolyte effects on the catalytic activity of ti ruo2 and ti iro2 electrodes oxidation of Isosafrole as a probe model
    Electrochimica Acta, 1999
    Co-Authors: C L P S Zanta, A R De Andrade, J F C Boodts
    Abstract:

    Abstract The electrocatalytic behavior of Ti/RuO2 and Ti/IrO2 electrodes was investigated as function of the supporting electrolyte and solvent. A decrease was observed in the electrochemically active area of the electrode as the cation size increases. The oxidation potential of a series of organic solvents tested showed a straight relationship with Gutmann's donor number: the higher the GDN the more easily is the solvent oxidized. Oxidation of Isosafrole, ISF, was used as a probe reaction to examine the influence of the supporting electrolyte cation size and the composition of the organic solvents on the electrocatalytic activity of the electrodes. The global catalytic activity for ISF oxidation is independent of the size of the supporting electrolyte cation and of the electrode material. For both electrode materials investigated it was verified that the following sequence holds for the influence of the solvent on the overall catalytic efficiency of ISF oxidation: AN>PC>DMSO≈DMF.