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Production and characterization of novel aryl sulfotransferases and their use in bioanalytics
Petránková, Barbora ; Bojarová, Pavla (advisor) ; Křížek, Tomáš (referee)
Polyphenols are the most common natural substances found in food. The largest group is represented by flavonoids, phenolic acids and catechols. Polyphenols are metabolized in the body during the biotransformation phase II, they can be sulfated, glucuronylated or methylated. To study biotransformation, it is necessary to have defined standards. Sulfated polyphenols can be prepared by enzymatic sulfation, which needs much milder reaction conditions compared to chemical sulfation. Prokaryotic sulfotransferases use 3'-phosphoadenosine-5'-phosphosulfate (PAPS) as a sulfate donor for sulfation, which is very expensive and difficult to regenerate. An alternative is the group of bacterial aryl sulfotransferases (EC 2.8.2.22), which catalyze the transfer of a sulfate group from a phenolic donor to a phenolic acceptor. Two bacterial aryl sulfotransferases from Desulfitobacterium hafniense and Escherichia coli have been described in the literature so far. The present thesis deals with the production, purification and biochemical characterization of two new bacterial aryl-sulfotransferases from Desulfosporosinus sp. HMP52 and Salmonella bongori. The enzymes were heterologously expressed in E. coli and purified by affinity chromatography. Their pH and temperature optimum, stability in organic solvents and...
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Influence of cultivation conditions relating to climatic change on the selected polyphenol content in grapevine plants
Tříska, Jan ; Balík, J. ; Vrchotová, Naděžda ; Mikeš, O.
Winegrowing is highly climate sensitive. Even small changes in temperature could have big impacts on the whole industry. Because of the relatively high crop value, many growers can aff ord to invest in adaptation resources that might not be feasible for less valuable crops. Th ere are two basic types of response to climate change: working to adapt to or manage the impacts experienced, and trying to prevent or minimize further change (mitigation). Th ese are not mutually exclusive, and in fact, both are increasingly regarded as necessary. In our contribution we will discuss the eff ects of drought, irrigation and cultivation in greenhouses in comparison to cultivation in vineyards on the content of trans-piceid and trans-resveratrol in white and blue varieties of Vitis vinifera plants.
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